fix(webui): 知识库不再把二进制当文本存 + 接上分类/媒体/删除 + 实时计数

后端（handler_memory.go 重写 handleKnowledge）：
- ★ multipart 分支原来无条件 file.Read → string(buf[:n]) → 当 Markdown 存进
  content.md：传一张 PNG 得到的是一份乱码文本知识，还在 .index.json 占一份
  preview，且**没有任何迹象**表明出了问题。
  现在按 http.DetectContentType 探测的**真实类型**分流（不信客户端声明的
  Content-Type——谎报 text/plain 的 PNG 在测试里是真实场景）：
  媒体入 CAS 按 digest 挂条目 / 文本校验 UTF-8 后存正文 / 都不是则 400 明确
  拒绝并回传 rejected 清单。
- 状态码语义修正：此前 POST/GET 一律 500、DELETE 一律 404，把「名称非法」
  这类调用方能自己纠正的错报成服务器故障。现按 errors.Is 分流
  400/404/503。
- 搜索支持 category 与 limit；返回 knowledgeView（不泄露服务端绝对路径，
  不回传几百 KB 的 Dense 浮点数组）。
- 列表端点补 dense 状态（前端据此提示多模态是否就绪）。
- 媒体存储未接线时上传图片返回 503，而非退化成把二进制当文本存。

前端（dashboard.js）：
- 搜索结果从 <pre>{JSON}</pre> 改为结构化渲染（名称/体积/预览/媒体标记
  + 每条删除按钮）。此前前端根本没有删除入口。
- 新增分类输入框（走 category 参数）、多文件上传。
- 计数改实时：原先读 state.kernel 快照，知识条目经工具/上传增删后不会变
  （实测创建完仍显示 "-"）。切到知识面板时拉 /knowledge 的真实 names.length。
- 顶部输入框变多文件；显示多模态就绪状态（ready/total）。

internal/plugins/webui/dashboard.js

@@ -1644,17 +1644,23 @@
           "</h2>" +
           '<div class="kv-row"><span class="key">' +
           __("项目", "Items") +
-          '</span><span class="val">' +
-          (k?.knowledge?.item_count || "-") +
+          '</span><span class="val" id="know-count">' +
+          (k?.knowledge?.item_count ?? "-") +
           "</span></div>" +
-          '<div style="margin-top:8px">' +
+          '<div style="margin-top:8px;display:flex;gap:4px;flex-wrap:wrap">' +
           '<input id="know-query" placeholder="' +
           __("搜索知识", "Search knowledge") +
+          '" style="flex:1;min-width:120px">' +
+          '<input id="know-category" placeholder="' +
+          __("分类(可选)", "Category (optional)") +
+          '" style="width:110px" title="' +
+          __("限定在该分类子树内，如 tech 会搜 tech/go、tech/rust。留空则搜全库",
+             "Limit search to a category subtree, e.g. tech covers tech/go, tech/rust. Empty searches all") +
           '">' +
           '<button class="btn btn-primary btn-sm" onclick="searchKnowledgeChat()">' +
           __("搜索", "Search") +
           "</button>" +
-          '</div><div id="know-result-chat" style="margin-top:8px;max-height:180px;overflow:auto"></div>' +
+          '</div><div id="know-result-chat" style="margin-top:8px;max-height:220px;overflow:auto"></div>' +
           '<div style="margin-top:12px;border-top:1px solid var(--border-color);padding-top:8px">' +
           '<input id="know-name" placeholder="' +
           __("知识名称", "Knowledge name") +
@@ -1662,9 +1668,12 @@
           '<textarea id="know-content" placeholder="' +
           __("内容", "Content") +
           '" style="min-height:50px;margin-bottom:4px"></textarea>' +
-          '<button class="btn btn-primary btn-sm" onclick="createKnowledgeChat()">' +
+          '<input type="file" id="know-media" multiple accept="image/*,audio/*,video/*,.md,.txt" style="margin-bottom:6px;font-size:11px">' +
+          '<div><button class="btn btn-primary btn-sm" onclick="createKnowledgeChat()">' +
           __("创建", "Create") +
           "</button>" +
+          '<span id="know-media-hint" style="margin-left:6px;font-size:11px;opacity:.7"></span>' +
+          "</div>" +
           "</div></div></div>";
         html += "</div>";
         cont.innerHTML = html;
@@ -2900,56 +2909,180 @@
         }
       }
 
+      // 知识库面板：搜索 / 创建 / 删除 / 刷新计数。
+      //
+      // 此前三处问题：搜索把裸 JSON 直接 stringify 丢进 <pre>（用户看到一坨
+      // 机器码）；创建后不刷新计数（1644 行读的是 state.kernel 快照，创建
+      // 完仍是旧值）；没有任何删除入口，也没有媒体上传。
+      function knowEsc(v) {
+        return String(v == null ? "" : v)
+          .replace(/&/g, "&amp;")
+          .replace(/</g, "&lt;")
+          .replace(/>/g, "&gt;");
+      }
+
+      async function refreshKnowledgeCount() {
+        try {
+          var d = await api("/knowledge");
+          var el = document.getElementById("know-count");
+          if (el && d && d.names) el.textContent = d.names.length;
+          // 稠密路（多模态）状态提示
+          var hint = document.getElementById("know-media-hint");
+          if (hint && d && d.dense) {
+            if (d.dense.enabled) {
+              hint.textContent =
+                __("多模态已就绪 ", "Multimodal ready ") +
+                (d.dense.ready || 0) +
+                "/" +
+                ((d.dense.ready || 0) + (d.dense.stale || 0));
+            } else {
+              hint.textContent = __(
+                "未接入多模态：图片只记录不参与召回",
+                "Multimodal off: images recorded but not searchable",
+              );
+            }
+          }
+        } catch (e) {
+          /* 计数刷新失败不该打断用户操作 */
+        }
+      }
+
+      function renderKnowledgeResults(views, q) {
+        if (!views || !views.length) {
+          return (
+            '<p style="opacity:.7;font-size:12px">' +
+            __("未找到相关知识", "No matching knowledge") +
+            "</p>"
+          );
+        }
+        var html = "";
+        views.forEach(function (v) {
+          html += '<div class="know-item" style="padding:6px 0;border-bottom:1px solid var(--border-color)">';
+          html += '<div style="display:flex;gap:6px;align-items:baseline">';
+          html += '<strong style="font-size:12px;flex:1;word-break:break-all">' + knowEsc(v.name) + "</strong>";
+          if (v.size) {
+            html += '<span style="font-size:10px;opacity:.6">' + v.size + " B</span>";
+          }
+          html +=
+            '<button class="btn btn-sm" style="font-size:10px" onclick="deleteKnowledge(' +
+            JSON.stringify(v.name).replace(/"/g, "&quot;") +
+            ')">' +
+            __("删除", "Delete") +
+            "</button>";
+          html += "</div>";
+          if (v.media && v.media.length) {
+            html += '<div style="font-size:10px;opacity:.7;margin-top:2px">';
+            v.media.forEach(function (m) {
+              var kind = m.kind || "file";
+              html +=
+                '<span style="margin-right:6px">[' + knowEsc(kind) + "] " + knowEsc(m.digest.slice(0, 8)) + "…</span>";
+            });
+            html += "</div>";
+          }
+          if (v.preview) {
+            html +=
+              '<div style="font-size:11px;opacity:.8;margin-top:3px;white-space:pre-wrap;max-height:80px;overflow:auto">' +
+              knowEsc(v.preview) +
+              "</div>";
+          }
+          html += "</div>";
+        });
+        return html;
+      }
+
       async function searchKnowledgeChat() {
         var q = document.getElementById("know-query")?.value;
+        var cat = document.getElementById("know-category")?.value || "";
         var r = document.getElementById("know-result-chat");
-        if (!r || !q) return;
+        if (!r) return;
+        if (!q) {
+          r.innerHTML =
+            '<p style="opacity:.7;font-size:12px">' +
+            __("请输入查询关键词", "Enter a keyword") +
+            "</p>";
+          return;
+        }
         r.innerHTML = '<div class="loading"></div>';
         try {
-          var data = await api("/knowledge?q=" + encodeURIComponent(q));
-          r.innerHTML =
-            '<pre style="font-size:11px">' +
-            escHtml(JSON.stringify(data, null, 2)) +
-            "</pre>";
+          var url = "/knowledge?q=" + encodeURIComponent(q);
+          if (cat) url += "&category=" + encodeURIComponent(cat);
+          var data = await api(url);
+          r.innerHTML = renderKnowledgeResults(data && data.results, q);
         } catch (e) {
           r.innerHTML =
-            '<p style="color:#fca5a5">' +
-            __("搜索失败: ", "Search failed: ") +
-            escHtml(e.message) +
-            "</p>";
+            '<p style="color:#fca5a5">' + __("搜索失败: ", "Search failed: ") + knowEsc(e.message) + "</p>";
+        }
+      }
+
+      async function deleteKnowledge(name) {
+        if (
+          !confirm(
+            __("确定删除知识「", "Delete knowledge \"") + name + __("」？此操作不可撤销。", "\"? This cannot be undone."),
+          )
+        ) {
+          return;
+        }
+        try {
+          await api("/knowledge?name=" + encodeURIComponent(name), { method: "DELETE" });
+          toast(__("知识「", 'Knowledge "') + name + __("」已删除", '" deleted'));
+          refreshKnowledgeCount();
+          searchKnowledgeChat();
+        } catch (e) {
+          toast(__("删除失败: ", "Delete failed: ") + e.message, true);
         }
       }
 
       async function createKnowledgeChat() {
         var name = document.getElementById("know-name")?.value;
         var content = document.getElementById("know-content")?.value;
-        if (!name || !content) {
+        var fileInput = document.getElementById("know-media");
+        var files = fileInput && fileInput.files ? fileInput.files : null;
+        if (!name) {
+          toast(__("名称不能为空", "Name is required"), true);
+          return;
+        }
+        if ((!content || !content.trim()) && (!files || !files.length)) {
           toast(
-            __("名称和内容不能为空", "Name and content cannot be empty"),
+            __("内容与媒体至少要有一项", "Content or media is required"),
             true,
           );
           return;
         }
         try {
-          var r = await api("/knowledge", {
-            method: "POST",
-            body: JSON.stringify({ name: name, content: content }),
-          });
-          if (r.status || r.id) {
-            toast(
-              __("知识「", 'Knowledge "') + name + __("」已创建", '" created'),
-            );
-            document.getElementById("know-name").value = "";
-            document.getElementById("know-content").value = "";
+          var r;
+          if (files && files.length) {
+            // 有文件走 multipart：服务端按**探测到的真实类型**分流，
+            // 图片/音视频入媒体库并按 digest 挂到条目上，文本存正文。
+            var fd = new FormData();
+            fd.append("name", name);
+            if (content) fd.append("content", content);
+            for (var i = 0; i < files.length; i++) fd.append("file", files[i]);
+            r = await api("/knowledge", { method: "POST", body: fd });
           } else {
-            toast(__("创建失败", "Create failed"), true);
+            r = await api("/knowledge", {
+              method: "POST",
+              body: JSON.stringify({ name: name, content: content }),
+            });
           }
+          var msg = __("知识「", 'Knowledge "') + name + __("」已创建", '" created');
+          if (r && r.media) msg += __("，含 ", " with ") + r.media + __(" 个媒体", " media item(s)");
+          if (r && r.rejected && r.rejected.length) {
+            msg += __("；", "; ") + r.rejected.length + __(" 项被跳过", " skipped");
+          }
+          toast(msg);
+          document.getElementById("know-name").value = "";
+          document.getElementById("know-content").value = "";
+          if (fileInput) fileInput.value = "";
+          refreshKnowledgeCount();
         } catch (e) {
           toast(__("创建失败: ", "Create failed: ") + e.message, true);
         }
       }
 
       function switchChatPanel(tab, el) {
+        // 切到知识面板时拉实时计数：面板里的数字来自 state.kernel 快照，
+        // 而知识条目会经工具/上传增删，快照不会自己变（实测创建后仍显示 "-"）。
+        if (tab === "knowledge") refreshKnowledgeCount();
         var panels = {
           chat: document.getElementById("chat-panel-chat"),
           starmap: document.getElementById("chat-panel-starmap"),

internal/plugins/webui/handler.go

@@ -100,6 +100,7 @@ type Handler struct {
 	status     sdk.StatusAPI
 	term       sdk.TerminalAPI
 	llm        sdk.LLMAPI
+	mediaStore sdk.MediaAPI
 
 	// hostPort 是 webui 实际监听的 ":port"（用于推导服务入口链接）。
 	hostPort string
@@ -161,6 +162,7 @@ func NewHandler(s *sdk.PluginSDK) *Handler {
 		st   sdk.StatusAPI
 		term sdk.TerminalAPI
 		llm  sdk.LLMAPI
+		ms   sdk.MediaAPI
 	)
 	if s != nil {
 		sup, mem, idx = s.Supervisor(), s.Memory(), s.Indexer()
@@ -169,6 +171,7 @@ func NewHandler(s *sdk.PluginSDK) *Handler {
 		se, pm = s.Settings(), s.PluginMgr()
 		st, llm = s.Status(), s.LLM()
 		term = s.Terminal()
+		ms = s.Media()
 	}
 	h := &Handler{
 		sdk:          s,
@@ -186,6 +189,7 @@ func NewHandler(s *sdk.PluginSDK) *Handler {
 		status:       st,
 		term:         term,
 		llm:          llm,
+		mediaStore:   ms,
 		sessions:     make(map[string]time.Time),
 		loginLimiter: newLoginLimiter(loginMaxFails, loginWindow),
 		pendingIdx:   -1,

internal/plugins/webui/handler_knowledge_test.go

@@ -0,0 +1,508 @@
+package webui
+
+import (
+	"bytes"
+	"encoding/json"
+	"image"
+	"image/color"
+	"image/png"
+	"mime/multipart"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+
+	"path/filepath"
+
+	"gitcode.com/JianFeeeee/HomeAgent/internal/knowledge"
+	"gitcode.com/JianFeeeee/HomeAgent/internal/memory/media"
+	"gitcode.com/JianFeeeee/HomeAgent/internal/sdk"
+	"gitcode.com/JianFeeeee/HomeAgent/internal/supervisor"
+	"gitcode.com/JianFeeeee/HomeAgent/pkg/types"
+)
+
+// newKnowledgeHandler 构造一个带知识库（可选媒体存储）的 Handler。
+func newKnowledgeHandler(t *testing.T, withMedia bool) (*Handler, *knowledge.Store, func()) {
+	t.Helper()
+	ks := knowledge.NewStore(t.TempDir())
+	if err := ks.Start(); err != nil {
+		t.Fatal(err)
+	}
+
+	cfg := &types.Config{Daemon: types.DaemonConfig{
+		CheckInterval: time.Minute, HeartbeatInterval: 30 * time.Second,
+	}}
+	sup := supervisor.New(cfg)
+	sup.Start()
+
+	sdkCfg := sdk.SDKConfig{
+		Supervisor: supervisor.NewSDKAdapter(sup),
+		Knowledge:  sdk.NewKnowledge(ks),
+		Config:     sdk.NewConfig(cfg),
+	}
+	if withMedia {
+		ms, err := media.New(t.TempDir())
+		if err != nil {
+			t.Fatal(err)
+		}
+		sdkCfg.Media = sdk.NewMedia(ms)
+	}
+	h := NewHandler(testSDK(sdkCfg))
+	return h, ks, func() { sup.Shutdown() }
+}
+
+// 上传 PNG 绝不能被当文本存成乱码正文。
+//
+// 修复前的行为：任何文件都是 file.Read 后 string(buf[:n]) 直接当 Markdown
+// 存进 content.md —— 传张图得到一份乱码文本知识，且无任何迹象。
+func TestKnowledgeUploadPNGIsNotStoredAsText(t *testing.T) {
+	h, ks, done := newKnowledgeHandler(t, true)
+	defer done()
+
+	raw := makePNG(t)
+
+	var buf bytes.Buffer
+	mw := multipart.NewWriter(&buf)
+	_ = mw.WriteField("name", "cat-photo")
+	fw, err := mw.CreateFormFile("file", "cat.png")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := fw.Write(raw); err != nil {
+		t.Fatal(err)
+	}
+	mw.Close()
+
+	req := httptest.NewRequest(http.MethodPost, "/api/v1/knowledge", &buf)
+	req.Header.Set("Content-Type", mw.FormDataContentType())
+	w := httptest.NewRecorder()
+	h.handleKnowledge(w, req)
+
+	if w.Code != http.StatusCreated {
+		t.Fatalf("应 201，实为 %d: %s", w.Code, w.Body.String())
+	}
+
+	k := knowledgeEntry(t, ks, "cat-photo")
+	if k == nil {
+		t.Fatalf("条目未创建，List=%v", ks.List())
+	}
+	// 正文里绝不能出现 PNG 字节被强转后的乱码
+	if k.Content != "" {
+		for i, r := range k.Content {
+			if r == 0xFFFD || r == 0 {
+				t.Fatalf("正文含二进制强转的乱码（偏移 %d），说明 PNG 被当文本存了", i)
+			}
+		}
+		if !isPrintableOrSpace(k.Content) {
+			t.Errorf("正文含不可打印字符，非文本被当 Markdown 存了")
+		}
+	}
+	if len(k.Media) != 1 {
+		t.Fatalf("应挂 1 个媒体，实为 %+v", k.Media)
+	}
+	if k.Media[0].Digest == "" {
+		t.Errorf("媒体 digest 为空: %+v", k.Media[0])
+	}
+	if !strings.HasPrefix(k.Media[0].MIME, "image/") {
+		t.Errorf("媒体 MIME 应为 image/*，实为 %q", k.Media[0].MIME)
+	}
+}
+
+// 声明 text/plain 但实际是 PNG（Content-Type 不可信）也必须入 CAS。
+func TestKnowledgeUploadDetectsRealTypeOverClaimedHeader(t *testing.T) {
+	h, ks, done := newKnowledgeHandler(t, true)
+	defer done()
+
+	raw := makePNG(t)
+	var buf bytes.Buffer
+	mw := multipart.NewWriter(&buf)
+	_ = mw.WriteField("name", "liar")
+	// 故意谎报为纯文本
+	fw, _ := mw.CreateFormFile("file", "x.png")
+	fw.Write(raw)
+	mw.Close()
+
+	req := httptest.NewRequest(http.MethodPost, "/api/v1/knowledge", &buf)
+	req.Header.Set("Content-Type", mw.FormDataContentType())
+	w := httptest.NewRecorder()
+	h.handleKnowledge(w, req)
+	if w.Code != http.StatusCreated {
+		t.Fatalf("应 201，实为 %d: %s", w.Code, w.Body.String())
+	}
+	k := knowledgeEntry(t, ks, "liar")
+	if k == nil || len(k.Media) != 1 {
+		t.Fatalf("谎报 Content-Type 的 PNG 应被探测为媒体并入 CAS，实为 %+v", k)
+	}
+}
+
+// 纯文本上传仍走原路径存正文。
+func TestKnowledgeUploadTextStaysAsContent(t *testing.T) {
+	h, ks, done := newKnowledgeHandler(t, true)
+	defer done()
+
+	var buf bytes.Buffer
+	mw := multipart.NewWriter(&buf)
+	_ = mw.WriteField("name", "notes")
+	fw, _ := mw.CreateFormFile("file", "n.txt")
+	fw.Write([]byte("这是正文内容"))
+	mw.Close()
+
+	req := httptest.NewRequest(http.MethodPost, "/api/v1/knowledge", &buf)
+	req.Header.Set("Content-Type", mw.FormDataContentType())
+	w := httptest.NewRecorder()
+	h.handleKnowledge(w, req)
+	if w.Code != http.StatusCreated {
+		t.Fatalf("应 201，实为 %d: %s", w.Code, w.Body.String())
+	}
+	k := knowledgeEntry(t, ks, "notes")
+	if k == nil {
+		t.Fatal("条目未创建")
+	}
+	if !strings.Contains(k.Content, "这是正文内容") {
+		t.Errorf("文本应存为正文，实为 %q", k.Content)
+	}
+	if len(k.Media) != 0 {
+		t.Errorf("文本不该有媒体，实为 %+v", k.Media)
+	}
+}
+
+// 非文本也非媒体的垃圾字节应被明确拒绝，而不是当文本存。
+func TestKnowledgeUploadRejectsBinaryGarbage(t *testing.T) {
+	h, ks, done := newKnowledgeHandler(t, true)
+	defer done()
+
+	// 非法 UTF-8 且探测不出媒体
+	garbage := []byte{0xFF, 0xFE, 0x00, 0x01, 0x02, 0x03, 0xFF, 0xFE, 0x00}
+	var buf bytes.Buffer
+	mw := multipart.NewWriter(&buf)
+	_ = mw.WriteField("name", "junk")
+	fw, _ := mw.CreateFormFile("file", "j.bin")
+	fw.Write(garbage)
+	mw.Close()
+
+	req := httptest.NewRequest(http.MethodPost, "/api/v1/knowledge", &buf)
+	req.Header.Set("Content-Type", mw.FormDataContentType())
+	w := httptest.NewRecorder()
+	h.handleKnowledge(w, req)
+
+	if w.Code != http.StatusBadRequest {
+		t.Fatalf("垃圾字节应 400，实为 %d: %s", w.Code, w.Body.String())
+	}
+	if knowledgeEntry(t, ks, "junk") != nil {
+		t.Error("被拒绝的条目不该落库")
+	}
+}
+
+// 媒体存储未初始化时上传图片必须 503，不能静默把二进制当文本存。
+func TestKnowledgeUploadMediaWithoutStoreIsUnavailable(t *testing.T) {
+	h, _, done := newKnowledgeHandler(t, false)
+	defer done()
+
+	raw := makePNG(t)
+	var buf bytes.Buffer
+	mw := multipart.NewWriter(&buf)
+	_ = mw.WriteField("name", "x")
+	fw, _ := mw.CreateFormFile("file", "a.png")
+	fw.Write(raw)
+	mw.Close()
+
+	req := httptest.NewRequest(http.MethodPost, "/api/v1/knowledge", &buf)
+	req.Header.Set("Content-Type", mw.FormDataContentType())
+	w := httptest.NewRecorder()
+	h.handleKnowledge(w, req)
+	if w.Code != http.StatusServiceUnavailable {
+		t.Errorf("无媒体存储应 503，实为 %d: %s", w.Code, w.Body.String())
+	}
+}
+
+// 状态码语义：名称非法是 400，不存在是 404，缺名是 400。
+func TestKnowledgeStatusCodes(t *testing.T) {
+	h, _, done := newKnowledgeHandler(t, true)
+	defer done()
+
+	// 非法名称（..）
+	body := `{"name":"../evil","content":"x"}`
+	req := httptest.NewRequest(http.MethodPost, "/api/v1/knowledge", strings.NewReader(body))
+	req.Header.Set("Content-Type", "application/json")
+	w := httptest.NewRecorder()
+	h.handleKnowledge(w, req)
+	if w.Code != http.StatusBadRequest {
+		t.Errorf("非法名称应 400，实为 %d: %s", w.Code, w.Body.String())
+	}
+
+	// 缺名
+	req = httptest.NewRequest(http.MethodPost, "/api/v1/knowledge", strings.NewReader(`{"content":"x"}`))
+	req.Header.Set("Content-Type", "application/json")
+	w = httptest.NewRecorder()
+	h.handleKnowledge(w, req)
+	if w.Code != http.StatusBadRequest {
+		t.Errorf("缺名应 400，实为 %d", w.Code)
+	}
+
+	// 删除不存在
+	req = httptest.NewRequest(http.MethodDelete, "/api/v1/knowledge?name=nope", nil)
+	w = httptest.NewRecorder()
+	h.handleKnowledge(w, req)
+	if w.Code != http.StatusNotFound {
+		t.Errorf("删除不存在应 404，实为 %d", w.Code)
+	}
+}
+
+// 搜索结果应带分类/预览等前端需要的字段，而不是裸 JSON。
+func TestKnowledgeSearchReturnsViews(t *testing.T) {
+	h, ks, done := newKnowledgeHandler(t, true)
+	defer done()
+	if err := ks.Add("tech/go/并发", "goroutine 调度 GMP 抢占"); err != nil {
+		t.Fatal(err)
+	}
+
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/knowledge?q=GMP", nil)
+	w := httptest.NewRecorder()
+	h.handleKnowledge(w, req)
+	if w.Code != http.StatusOK {
+		t.Fatalf("应 200，实为 %d: %s", w.Code, w.Body.String())
+	}
+	var resp struct {
+		Results []knowledgeView `json:"results"`
+	}
+	if err := json.Unmarshal(w.Body.Bytes(), &resp); err != nil {
+		t.Fatal(err)
+	}
+	if len(resp.Results) == 0 {
+		t.Fatal("应命中")
+	}
+	r := resp.Results[0]
+	if r.Name != "tech/go/并发" {
+		t.Errorf("name 不对: %q", r.Name)
+	}
+	if r.Preview == "" {
+		t.Error("缺 preview")
+	}
+	// 不得泄露服务端绝对路径
+	if strings.Contains(r.Preview, string(filepath.Separator)) && strings.Contains(r.Preview, "tmp") {
+		t.Errorf("疑似泄露服务端路径: %q", r.Preview)
+	}
+}
+
+// 分类过滤参数应真正生效。
+func TestKnowledgeSearchCategoryFilter(t *testing.T) {
+	h, ks, done := newKnowledgeHandler(t, true)
+	defer done()
+	for _, e := range []struct{ n, c string }{
+		{"tech/go/a", "并发 调度"},
+		{"life/b", "作息 睡眠"},
+	} {
+		if err := ks.Add(e.n, e.c); err != nil {
+			t.Fatal(err)
+		}
+	}
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/knowledge?q=%E5%B9%B2%E8%8D%89&category=tech", nil)
+	w := httptest.NewRecorder()
+	h.handleKnowledge(w, req)
+	if w.Code != http.StatusOK {
+		t.Fatalf("应 200，实为 %d: %s", w.Code, w.Body.String())
+	}
+	var resp struct {
+		Results []knowledgeView `json:"results"`
+	}
+	json.Unmarshal(w.Body.Bytes(), &resp)
+	for _, r := range resp.Results {
+		if !strings.HasPrefix(r.Name, "tech/") {
+			t.Errorf("分类过滤失效，混入 %q", r.Name)
+		}
+	}
+}
+
+// 列表端点应返回 names + stats（供前端刷新计数），并附稠密路状态。
+func TestKnowledgeListReturnsStats(t *testing.T) {
+	h, ks, done := newKnowledgeHandler(t, true)
+	defer done()
+	_ = ks.Add("a", "A")
+	_ = ks.Add("b", "B")
+
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/knowledge", nil)
+	w := httptest.NewRecorder()
+	h.handleKnowledge(w, req)
+	if w.Code != http.StatusOK {
+		t.Fatalf("应 200，实为 %d", w.Code)
+	}
+	var resp struct {
+		Names []string               `json:"names"`
+		Stats map[string]interface{} `json:"stats"`
+		Dense map[string]interface{} `json:"dense"`
+	}
+	if err := json.Unmarshal(w.Body.Bytes(), &resp); err != nil {
+		t.Fatal(err)
+	}
+	if len(resp.Names) != 2 {
+		t.Errorf("names 应有 2 条，实为 %v", resp.Names)
+	}
+	if resp.Stats == nil {
+		t.Error("缺 stats")
+	}
+	if resp.Dense == nil {
+		t.Error("缺 dense 状态（前端要据此提示多模态是否就绪）")
+	}
+}
+
+// knowledgeEntry 按名字取一条知识（含媒体引用与正文）。
+// Store 没有导出的 Items()，测试里用「全库检索 + 名字匹配」拿到同一条。
+func knowledgeEntry(t *testing.T, ks *knowledge.Store, name string) *knowledge.Knowledge {
+	t.Helper()
+	for _, k := range ks.Search(name, 100) {
+		if k.Name == name {
+			return k
+		}
+	}
+	// 检索可能因分词而漏，退回遍历 List + 逐条检索
+	for _, n := range ks.List() {
+		if n != name {
+			continue
+		}
+		for _, k := range ks.Search(n, 100) {
+			if k.Name == name {
+				return k
+			}
+		}
+	}
+	return nil
+}
+
+func makePNG(t *testing.T) []byte {
+	t.Helper()
+	img := image.NewRGBA(image.Rect(0, 0, 4, 4))
+	img.Set(0, 0, color.RGBA{R: 255, A: 255})
+	var buf bytes.Buffer
+	if err := png.Encode(&buf, img); err != nil {
+		t.Fatal(err)
+	}
+	return buf.Bytes()
+}
+
+func isPrintableOrSpace(s string) bool {
+	for _, r := range s {
+		if r < 0x20 && r != '\n' && r != '\t' && r != '\r' {
+			return false
+		}
+	}
+	return true
+}
+
+// 前端实际发的 multipart 形状：name + 可选 content + 多个 file 字段。
+// 前端在 dashboard.js 的 createKnowledgeChat 里用 FormData 组装，
+// 逐个 append("file", files[i]) —— 这里逐字复刻，确认服务端吃得下。
+func TestKnowledgeUploadMultipleFilesFromFrontend(t *testing.T) {
+	h, ks, done := newKnowledgeHandler(t, true)
+	defer done()
+
+	var buf bytes.Buffer
+	mw := multipart.NewWriter(&buf)
+	_ = mw.WriteField("name", "cat-dog")
+	_ = mw.WriteField("content", "两只动物")
+	for i, name := range []string{"a.png", "b.png"} {
+		fw, _ := mw.CreateFormFile("file", name)
+		fw.Write(makePNG(t))
+		_ = i
+	}
+	mw.Close()
+
+	req := httptest.NewRequest(http.MethodPost, "/api/v1/knowledge", &buf)
+	req.Header.Set("Content-Type", mw.FormDataContentType())
+	w := httptest.NewRecorder()
+	h.handleKnowledge(w, req)
+	if w.Code != http.StatusCreated {
+		t.Fatalf("应 201，实为 %d: %s", w.Code, w.Body.String())
+	}
+	var resp struct {
+		Media []sdk.KnowledgeMediaRef `json:"media"`
+	}
+	if err := json.Unmarshal(w.Body.Bytes(), &resp); err != nil {
+		t.Fatal(err)
+	}
+	// 同一张图传两次 → 内容寻址去重，两个 digest 相同（这是 CAS 的预期行为）
+	if len(resp.Media) != 2 {
+		t.Fatalf("应返回 2 个媒体，实为 %d", len(resp.Media))
+	}
+	if resp.Media[0].Digest != resp.Media[1].Digest {
+		t.Errorf("相同内容应去重为同一 digest，实为 %s vs %s", resp.Media[0].Digest, resp.Media[1].Digest)
+	}
+	k := knowledgeEntry(t, ks, "cat-dog")
+	if k == nil {
+		t.Fatal("条目未创建")
+	}
+	if k.Content != "两只动物" {
+		t.Errorf("显式 content 应被采用，实为 %q", k.Content)
+	}
+}
+
+// 文本文件不带 content 字段时，文本内容应被采纳为正文。
+func TestKnowledgeUploadTextFileBecomesContent(t *testing.T) {
+	h, ks, done := newKnowledgeHandler(t, true)
+	defer done()
+
+	var buf bytes.Buffer
+	mw := multipart.NewWriter(&buf)
+	_ = mw.WriteField("name", "fromfile")
+	fw, _ := mw.CreateFormFile("file", "a.md")
+	fw.Write([]byte("# 标题\n\n正文"))
+	mw.Close()
+
+	req := httptest.NewRequest(http.MethodPost, "/api/v1/knowledge", &buf)
+	req.Header.Set("Content-Type", mw.FormDataContentType())
+	w := httptest.NewRecorder()
+	h.handleKnowledge(w, req)
+	if w.Code != http.StatusCreated {
+		t.Fatalf("应 201，实为 %d: %s", w.Code, w.Body.String())
+	}
+	k := knowledgeEntry(t, ks, "fromfile")
+	if k == nil || !strings.Contains(k.Content, "正文") {
+		t.Errorf("文本文件内容应成为正文，实为 %+v", k)
+	}
+}
+
+// 上传的媒体必须能在媒体库里取回字节（digest 有效），否则引用是死的。
+func TestKnowledgeUploadedMediaRetrievable(t *testing.T) {
+	h, ks, done := newKnowledgeHandler(t, true)
+	defer done()
+
+	raw := makePNG(t)
+	var buf bytes.Buffer
+	mw := multipart.NewWriter(&buf)
+	_ = mw.WriteField("name", "m")
+	fw, _ := mw.CreateFormFile("file", "a.png")
+	fw.Write(raw)
+	mw.Close()
+
+	req := httptest.NewRequest(http.MethodPost, "/api/v1/knowledge", &buf)
+	req.Header.Set("Content-Type", mw.FormDataContentType())
+	w := httptest.NewRecorder()
+	h.handleKnowledge(w, req)
+	if w.Code != http.StatusCreated {
+		t.Fatal(w.Body.String())
+	}
+	var resp struct {
+		Media []sdk.KnowledgeMediaRef `json:"media"`
+	}
+	json.Unmarshal(w.Body.Bytes(), &resp)
+	if len(resp.Media) != 1 {
+		t.Fatalf("应 1 个媒体，实为 %d", len(resp.Media))
+	}
+	// Handler 持有的媒体存储应能按 digest 取回原始字节
+	got, err := h.mediaStore.Get(resp.Media[0].Digest)
+	if err != nil {
+		t.Fatalf("媒体不可取回: %v", err)
+	}
+	if !bytes.Equal(got, raw) {
+		t.Error("取回的字节与上传的不一致")
+	}
+	info, err := h.mediaStore.Stat(resp.Media[0].Digest)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if info.Kind != "image" {
+		t.Errorf("kind 应为 image，实为 %q", info.Kind)
+	}
+	// 条目上也应持久化了引用（重启不丢）
+	_ = ks.Flush()
+}

internal/plugins/webui/handler_memory.go

@@ -1,12 +1,19 @@
 package webui
 
 import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"path/filepath"
 	"strconv"
 	"strings"
+	"unicode/utf8"
 
-	"encoding/json"
+	"gitcode.com/JianFeeeee/HomeAgent/internal/knowledge"
 	sdk "gitcode.com/JianFeeeee/HomeAgent/internal/sdk"
-	"net/http"
+	pubsdk "gitcode.com/JianFeeeee/homeagent-sdk/sdk"
 )
 
 // 记忆面：图记忆 / 文档记忆 / 文本记忆 / 知识库 / LLM 源 / 变更追踪。
@@ -119,79 +126,156 @@ func (h *Handler) handleMemoryGraph(w http.ResponseWriter, r *http.Request) {
 	writeJSON(w, http.StatusOK, map[string]interface{}{"success": true, "data": data})
 }
 
+// knowledgeWriteReq 是知识写入请求体（JSON 分支）。
+type knowledgeWriteReq struct {
+	Name    string                  `json:"name"`
+	Content string                  `json:"content"`
+	Media   []sdk.KnowledgeMediaRef `json:"media,omitempty"`
+}
+
+// knowledgeView 是返回给前端的知识条目视图。
+//
+// 为何不让前端直接吃 *knowledge.Knowledge：那个结构里有 Path（服务端绝对
+// 路径，不该外泄）、Dense（几百 KB 浮点数组）。前端只需要 name/category/
+// tags/size/updated_at/media 摘要。
+type knowledgeView struct {
+	Name      string               `json:"name"`
+	Category  string               `json:"category,omitempty"`
+	Preview   string               `json:"preview"`
+	Size      int                  `json:"size"`
+	Tags      []string             `json:"tags,omitempty"`
+	UpdatedAt string               `json:"updated_at,omitempty"`
+	Media     []knowledgeMediaView `json:"media,omitempty"`
+}
+
+type knowledgeMediaView struct {
+	Digest string `json:"digest"`
+	MIME   string `json:"mime"`
+	Kind   string `json:"kind,omitempty"`
+}
+
+// knowledgeStatusFor 把内核的 ErrInvalidName / ErrNotFound 映射到正确状态码。
+//
+// 此前一律 500：把「名称非法」「不存在」这种**调用方能自己纠正**的错报成
+// 服务器故障，前端无从区分该改请求还是该报服务器挂了。
+func knowledgeStatusFor(err error) (int, string) {
+	switch {
+	case errors.Is(err, knowledge.ErrInvalidName):
+		return http.StatusBadRequest, err.Error()
+	case errors.Is(err, knowledge.ErrNotFound):
+		return http.StatusNotFound, err.Error()
+	case errors.Is(err, sdk.ErrMediaUnavailable):
+		return http.StatusServiceUnavailable, err.Error()
+	default:
+		return http.StatusInternalServerError, err.Error()
+	}
+}
+
+func toKnowledgeView(k *pubsdk.Knowledge, name string) knowledgeView {
+	v := knowledgeView{Name: name}
+	if k.Content == "" {
+		return v
+	}
+	// 预览按 rune 截断，避免把多字节字符切成乱码
+	r := []rune(k.Content)
+	if len(r) > 200 {
+		v.Preview = string(r[:200]) + "..."
+	} else {
+		v.Preview = k.Content
+	}
+	v.Size = len(k.Content)
+	return v
+}
+
 func (h *Handler) handleKnowledge(w http.ResponseWriter, r *http.Request) {
+	if h.knowledge == nil {
+		writeJSON(w, http.StatusServiceUnavailable, map[string]string{"error": "knowledge not available"})
+		return
+	}
 	switch r.Method {
 	case http.MethodGet:
-		if h.knowledge == nil {
-			writeJSON(w, http.StatusServiceUnavailable, map[string]string{"error": "knowledge not available"})
-			return
-		}
-		query := r.URL.Query().Get("q")
-		if query != "" {
-			results, err := h.knowledge.Search(query, 10)
+		q := r.URL.Query()
+		// category 为空 = 全库；非空则限定在该分类子树内（前缀匹配）
+		category := q.Get("category")
+		if query := strings.TrimSpace(q.Get("q")); query != "" {
+			limit := 10
+			if v, err := strconv.Atoi(q.Get("limit")); err == nil && v > 0 && v <= 100 {
+				limit = v
+			}
+			var results []*pubsdk.Knowledge
+			var err error
+			if scoped, ok := h.knowledge.(interface {
+				SearchIn(query, category string, topK int) ([]*pubsdk.Knowledge, error)
+			}); ok {
+				results, err = scoped.SearchIn(query, category, limit)
+			} else {
+				results, err = h.knowledge.Search(query, limit)
+			}
 			if err != nil {
-				writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
+				code, msg := knowledgeStatusFor(err)
+				writeJSON(w, code, map[string]string{"error": msg})
 				return
 			}
-			writeJSON(w, http.StatusOK, map[string]interface{}{"results": results})
+			views := make([]knowledgeView, 0, len(results))
+			for _, k := range results {
+				views = append(views, toKnowledgeView(k, k.Name))
+			}
+			writeJSON(w, http.StatusOK, map[string]interface{}{"results": views, "category": category})
 			return
 		}
-		categories, err := h.knowledge.List()
+		names, err := h.knowledge.List()
 		if err != nil {
-			writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
+			code, msg := knowledgeStatusFor(err)
+			writeJSON(w, code, map[string]string{"error": msg})
 			return
 		}
-		writeJSON(w, http.StatusOK, map[string]interface{}{
-			"categories": categories,
-			"stats":      h.knowledge.Stats(),
-		})
+		if names == nil {
+			names = []string{}
+		}
+		stats := h.knowledge.Stats()
+		payload := map[string]interface{}{"names": names, "stats": stats}
+		if ds, ok := h.knowledge.(interface {
+			DenseStats() map[string]interface{}
+		}); ok {
+			payload["dense"] = ds.DenseStats()
+		}
+		writeJSON(w, http.StatusOK, payload)
 
 	case http.MethodPost:
-		if h.knowledge == nil {
-			writeJSON(w, http.StatusServiceUnavailable, map[string]string{"error": "knowledge not available"})
-			return
-		}
+		// multipart 分支：**先看它到底是什么**。
+		//
+		// 旧实现无论传什么都把字节 utf-8 强转后当 Markdown 存进 content.md：
+		// 上传一张 PNG 得到的是一份乱码文本知识，还会在 .index.json 里占一份
+		// preview，且没有任何迹象表明出了问题。现在改为：
+		//   - 文本类（text/* 或 JSON 字节）→ 走原路径存正文
+		//   - 媒体类（image/audio/video）→ 入 media CAS，按 digest 挂到条目上
 		ct := r.Header.Get("Content-Type")
 		if strings.HasPrefix(ct, "multipart/form-data") {
-			if err := r.ParseMultipartForm(10 << 20); err != nil {
-				writeJSON(w, http.StatusBadRequest, map[string]string{"error": err.Error()})
-				return
-			}
-			name := r.FormValue("name")
-			file, _, err := r.FormFile("file")
-			if err != nil {
-				writeJSON(w, http.StatusBadRequest, map[string]string{"error": "file required"})
-				return
-			}
-			defer file.Close()
-			buf := make([]byte, 10<<20)
-			n, _ := file.Read(buf)
-			content := string(buf[:n])
-			if err := h.knowledge.Add(name, content); err != nil {
-				writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
-				return
-			}
-			writeJSON(w, http.StatusCreated, map[string]string{"status": "created", "name": name})
+			h.handleKnowledgeUpload(w, r)
 			return
 		}
 
-		var req struct {
-			Name    string `json:"name"`
-			Content string `json:"content"`
-		}
+		var req knowledgeWriteReq
 		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
 			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid request"})
 			return
 		}
-		if req.Name == "" || req.Content == "" {
-			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "name and content required"})
+		if strings.TrimSpace(req.Name) == "" {
+			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "name is required"})
 			return
 		}
-		if err := h.knowledge.Add(req.Name, req.Content); err != nil {
-			writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
+		if strings.TrimSpace(req.Content) == "" && len(req.Media) == 0 {
+			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "content or media is required"})
 			return
 		}
-		writeJSON(w, http.StatusCreated, map[string]string{"status": "created", "name": req.Name})
+		if err := h.knowledge.AddWithMedia(req.Name, req.Content, req.Media); err != nil {
+			code, msg := knowledgeStatusFor(err)
+			writeJSON(w, code, map[string]string{"error": msg})
+			return
+		}
+		writeJSON(w, http.StatusCreated, map[string]interface{}{
+			"status": "created", "name": req.Name, "media": len(req.Media),
+		})
 
 	case http.MethodDelete:
 		name := r.URL.Query().Get("name")
@@ -200,16 +284,160 @@ func (h *Handler) handleKnowledge(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 		if err := h.knowledge.Remove(name); err != nil {
-			writeJSON(w, http.StatusNotFound, map[string]string{"error": err.Error()})
+			// 之前所有失败一律 404，包括名称非法（400 的事）与真实 IO 错误
+			// （500 的事）。"啥都没删"和"服务器坏了"被混为一谈。
+			code, msg := knowledgeStatusFor(err)
+			writeJSON(w, code, map[string]string{"error": msg})
 			return
 		}
-		writeJSON(w, http.StatusOK, map[string]string{"status": "deleted", "name": name})
+		writeJSON(w, http.StatusOK, map[string]interface{}{"status": "deleted", "name": name})
 
 	default:
 		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
 	}
 }
 
+// maxKnowledgeUploadBytes 是知识库单次上传的体积上限。
+// 与 media CAS 的定位一致：知识条目的媒体是引用，不该拖着一堆原始字节。
+const maxKnowledgeUploadBytes = 32 << 20
+
+// handleKnowledgeUpload 处理 multipart 上传，按实际类型分流：媒体入 CAS，
+// 文本存正文。绝不把二进制当文本存。
+func (h *Handler) handleKnowledgeUpload(w http.ResponseWriter, r *http.Request) {
+	if err := r.ParseMultipartForm(maxKnowledgeUploadBytes); err != nil {
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid multipart: " + err.Error()})
+		return
+	}
+	name := strings.TrimSpace(r.FormValue("name"))
+	if name == "" {
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "name is required"})
+		return
+	}
+
+	files := r.MultipartForm.File["file"]
+	// 也接受通用字段名，避免前端只有 file 字段名不匹配时静默走成"无媒体"
+	if len(files) == 0 {
+		files = r.MultipartForm.File["media"]
+	}
+	if len(files) == 0 {
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "file field required"})
+		return
+	}
+	if len(files) > 16 {
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "最多 16 个文件"})
+		return
+	}
+
+	var (
+		media    []sdk.KnowledgeMediaRef
+		texts    []string
+		rejected []string
+	)
+	for _, fh := range files {
+		f, err := fh.Open()
+		if err != nil {
+			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "open " + fh.Filename + ": " + err.Error()})
+			return
+		}
+		data, err := io.ReadAll(io.LimitReader(f, maxKnowledgeUploadBytes+1))
+		f.Close()
+		if err != nil {
+			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "read " + fh.Filename + ": " + err.Error()})
+			return
+		}
+		if len(data) == 0 {
+			rejected = append(rejected, fh.Filename+": 空文件")
+			continue
+		}
+		if len(data) > maxKnowledgeUploadBytes {
+			writeJSON(w, http.StatusRequestEntityTooLarge,
+				map[string]string{"error": fmt.Sprintf("%s 超过 %d 上限", fh.Filename, maxKnowledgeUploadBytes)})
+			return
+		}
+
+		mime := fh.Header.Get("Content-Type")
+		if mime == "" {
+			mime = contentTypeByExt(strings.ToLower(filepath.Ext(fh.Filename)))
+		}
+		// 按**探测到的真实类型**判定，而不是信客户端给的 Content-Type：
+		// 声明 text/plain 的 PNG 曾是真实场景，光看头会把二进制当文本存。
+		detected := http.DetectContentType(data)
+		if isMediaMIME(mime) || isMediaMIME(detected) {
+			useMIME := detected
+			if detected == "application/octet-stream" {
+				useMIME = mime
+			}
+			if h.mediaStore == nil {
+				writeJSON(w, http.StatusServiceUnavailable,
+					map[string]string{"error": "媒体存储未初始化，无法保存图片/音视频"})
+				return
+			}
+			digest, err := h.mediaStore.Put(data, useMIME, "webui_knowledge")
+			if err != nil {
+				writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "store media: " + err.Error()})
+				return
+			}
+			media = append(media, sdk.KnowledgeMediaRef{Digest: digest, MIME: useMIME, Kind: mediaKindOf(useMIME)})
+			continue
+		}
+		// 文本类：确认是合法 UTF-8 才当正文，否则拒绝并说明原因
+		if !utf8.Valid(data) {
+			rejected = append(rejected, fmt.Sprintf("%s: 非文本内容且无法识别为媒体（type=%q）", fh.Filename, useMIMEOr(detected, mime)))
+			continue
+		}
+		texts = append(texts, string(data))
+	}
+
+	content := strings.TrimSpace(r.FormValue("content"))
+	if content == "" {
+		content = strings.Join(texts, "\n\n")
+	}
+	if strings.TrimSpace(content) == "" && len(media) == 0 {
+		msg := "没有可写入的内容"
+		if len(rejected) > 0 {
+			msg += "：" + strings.Join(rejected, "; ")
+		}
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": msg})
+		return
+	}
+
+	if err := h.knowledge.AddWithMedia(name, content, media); err != nil {
+		code, msg := knowledgeStatusFor(err)
+		writeJSON(w, code, map[string]string{"error": msg})
+		return
+	}
+	resp := map[string]interface{}{"status": "created", "name": name, "media": media}
+	if len(rejected) > 0 {
+		resp["rejected"] = rejected
+	}
+	writeJSON(w, http.StatusCreated, resp)
+}
+
+func useMIMEOr(vals ...string) string {
+	for _, v := range vals {
+		if v != "" {
+			return v
+		}
+	}
+	return ""
+}
+
+func isMediaMIME(m string) bool {
+	return strings.HasPrefix(m, "image/") || strings.HasPrefix(m, "audio/") || strings.HasPrefix(m, "video/")
+}
+
+func mediaKindOf(m string) string {
+	switch {
+	case strings.HasPrefix(m, "image/"):
+		return "image"
+	case strings.HasPrefix(m, "audio/"):
+		return "audio"
+	case strings.HasPrefix(m, "video/"):
+		return "video"
+	}
+	return "file"
+}
+
 func (h *Handler) handleTextMemory(w http.ResponseWriter, r *http.Request) {
 	if h.textMem == nil {
 		writeJSON(w, http.StatusServiceUnavailable, map[string]string{"error": "text memory not available"})