feat(gui): Electron desktop with embedded core, tray, autostart, win/linux packaging

- cmd/gui: Electron shell (Clash-Verge style) embedding the full WebUI 1:1
  - embedded llmsproxy core (luajit) with auto-generated profile
  - key stored in keys[] (non-seed) so no replace-the-key warning
  - gw_key cookie injection: web UI works without login
  - side-rail toggles for autostart / silent start
  - system tray with status + controls, silent start (--silent)
  - win cross-build (mingw luajit exe + dll) / deb / AppImage via electron-builder
- Makefile: build / gui / gui-dist / gui-deb / gui-win targets
- README: desktop GUI section
- lua(adapter): opencode normalizes non-whitelisted roles to system

internal/lua/adapters/opencode.lua

@@ -16,6 +16,17 @@ adapter.headers = {
 -- zen 上游 schema 只接受 text content part（无视觉/音频能力）：多模态 part
 -- （image_url / input_audio / file 等）一律剥离；因此失去全部 content 的
 -- 消息整条丢弃，避免上游 "unknown variant `image_url`, expected `text`"。
+-- zen 上游角色白名单只有 system / user / assistant / tool / latest_reminder：
+-- OpenAI 的 developer（及 function 等）不在其中，直接透传会触发上游
+-- "unknown variant `developer`, expected one of ..." 错误；统一归一化为 system。
+local ROLE_WHITELIST = {
+    system = true,
+    user = true,
+    assistant = true,
+    tool = true,
+    latest_reminder = true,
+}
+
 function adapter.transform_request(raw_body)
     local ok, req = pcall(json.decode, raw_body)
     if not ok then return raw_body end
@@ -24,6 +35,9 @@ function adapter.transform_request(raw_body)
     if req.messages then
         local kept = {}
         for _, msg in ipairs(req.messages) do
+            if type(msg.role) == "string" and not ROLE_WHITELIST[msg.role] then
+                msg.role = "system"
+            end
             msg.reasoning_content = nil
             local drop = false
             if type(msg.content) == "table" then

internal/lua/vm_test.go

@@ -302,3 +302,71 @@ func TestMultimodalTransform(t *testing.T) {
 		t.Fatalf("openai passthrough lost multimodal content: %s", po)
 	}
 }
+
+func TestOpenCodeAdapterNormalizesDeveloperRole(t *testing.T) {
+	vm := NewVM(freshAdapterDir(t))
+	if err := vm.Start(); err != nil {
+		t.Fatalf("start: %v", err)
+	}
+	defer vm.Stop()
+
+	raw := `{"model":"zen","messages":[` +
+		`{"role":"developer","content":"be concise"},` +
+		`{"role":"user","content":"hi"},` +
+		`{"role":"assistant","content":"hello"},` +
+		`{"role":"function","content":"{\"a\":1}"},` +
+		`{"role":"latest_reminder","content":"remind"}]}`
+	out, err := vm.Transform("opencode", "transform_request", raw)
+	if err != nil {
+		t.Fatalf("transform_request: %v", err)
+	}
+	var req struct {
+		Messages []struct {
+			Role string `json:"role"`
+		} `json:"messages"`
+	}
+	if err := json.Unmarshal([]byte(out), &req); err != nil {
+		t.Fatalf("output not JSON: %v\n%s", err, out)
+	}
+	want := []string{"system", "user", "assistant", "system", "latest_reminder"}
+	if len(req.Messages) != len(want) {
+		t.Fatalf("got %d messages, want %d: %s", len(req.Messages), len(want), out)
+	}
+	for i, w := range want {
+		if req.Messages[i].Role != w {
+			t.Errorf("message %d role = %q, want %q", i, req.Messages[i].Role, w)
+		}
+	}
+}
+
+func TestOpenCodeAdapterKeepsWhitelistedRolesAndDropsMultimodal(t *testing.T) {
+	vm := NewVM(freshAdapterDir(t))
+	if err := vm.Start(); err != nil {
+		t.Fatalf("start: %v", err)
+	}
+	defer vm.Stop()
+
+	raw := `{"messages":[` +
+		`{"role":"system","content":"sys"},` +
+		`{"role":"user","content":[{"type":"text","text":"keep"},{"type":"image_url","url":"x"}]},` +
+		`{"role":"user","content":[{"type":"image_url","url":"x"}]}]}`
+	out, err := vm.Transform("opencode", "transform_request", raw)
+	if err != nil {
+		t.Fatalf("transform_request: %v", err)
+	}
+	var req struct {
+		Messages []struct {
+			Role    string `json:"role"`
+			Content any    `json:"content"`
+		} `json:"messages"`
+	}
+	if err := json.Unmarshal([]byte(out), &req); err != nil {
+		t.Fatalf("output not JSON: %v\n%s", err, out)
+	}
+	if len(req.Messages) != 2 {
+		t.Fatalf("got %d messages, want 2 (multimodal-only dropped): %s", len(req.Messages), out)
+	}
+	if req.Messages[0].Role != "system" || req.Messages[1].Role != "user" {
+		t.Fatalf("unexpected roles: %s", out)
+	}
+}