fix(examples): 全插件安全审查修复（qq/a2a/memo/calendar/rss/browser/bili/recoverydiag）

审查发现并修复 7 项问题：
- P1 qq: downloadURL 裸 http.Get 无超时 → 120s client
- P2 a2a: inbound http.Server 零超时 → Read 30s/Write 120s/Idle 60s
- P3 bili: output_dir 配置项零校验 → 系统目录黑名单（/、/etc、/usr、/var 等）
- P4 recoverydiag: db_path LLM 可控任意 sqlite → 强制限制 data 目录内
- P5 memo/calendar/rss: os.WriteFile 直写 → atomicWriteJSON (temp+rename)
- P6 qq: 3 处后台 goroutine（已读/rcon转发/下载）加 panic recover
- P7 browser: dump-dom failback Kill 后补 wait 回收僵尸进程

recoverydiag 此前被 .gitignore 排除，但其 db_path 安全修复
属生产代码，故取消忽略并入库。

全部经 plugindev 重打包升版安装验证 config_kept=true。

example/recoverydiag/diag_test.go

@@ -0,0 +1,153 @@
+package main
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+var realCfg = "/home/newqqagent/config.db"
+var realLog = "/home/newqqagent/log"
+
+func TestDiagTriage(t *testing.T) {
+	p := &Plugin{name: "recoverydiag"}
+
+	cases := []struct {
+		name string
+		args map[string]interface{}
+		want string
+	}{
+		{"signal", map[string]interface{}{"exit_code": 0, "signal": "SIGSEGV"}, "process_death"},
+		{"oom", map[string]interface{}{"exit_code": 0, "signal": "SIGKILL", "crash_reason": "oom-kill"}, "process_starvation"},
+		{"nonzero", map[string]interface{}{"exit_code": 1}, "process_death"},
+		{"healthy", map[string]interface{}{"exit_code": 0}, "normal_stop"},
+		{"alive", map[string]interface{}{"still_alive": true, "signal": "SIGKILL"}, "config_unreachable"},
+	}
+	for _, c := range cases {
+		r, _ := p.handleTriage(c.args)
+		m, ok := r.(map[string]interface{})
+		if !ok {
+			t.Fatalf("%s: not a map", c.name)
+		}
+		if got, _ := m["class"].(string); got != c.want {
+			t.Errorf("%s: class = %q, want %q", c.name, got, c.want)
+		}
+	}
+}
+
+func TestDiagDB(t *testing.T) {
+	if _, err := os.Stat(realCfg); err != nil {
+		t.Skip("config.db not present, skipping")
+	}
+	p := &Plugin{name: "recoverydiag"}
+	r, err := p.handleDB(map[string]interface{}{"db_path": realCfg})
+	if err != nil {
+		t.Fatalf("handleDB: %v", err)
+	}
+	m := r.(map[string]interface{})
+	t.Logf("integrity=%v sources=%v verdict=%v summary=%v", m["integrity"], m["source_count"], m["verdict"], m["summary"])
+	if m["integrity"] != "ok" {
+		t.Errorf("integrity = %v, want ok", m["integrity"])
+	}
+	if m["source_count"] == 0 {
+		t.Errorf("source_count == 0, expected LLM sources")
+	}
+	if got, _ := m["source_failed"].(int); got != 0 {
+		t.Errorf("source_failed = %d, want 0 (all sources OK): %v", got, m["missing_fields"])
+	}
+}
+
+func TestDiagLogScan(t *testing.T) {
+	if _, err := os.Stat(realLog); err != nil {
+		t.Skip("log dir not present, skipping")
+	}
+	p := &Plugin{name: "recoverydiag"}
+	r, err := p.handleLogScan(map[string]interface{}{
+		"log_dir":       realLog,
+		"since_minutes": 60 * 24 * 3,
+	})
+	if err != nil {
+		t.Fatalf("handleLogScan: %v", err)
+	}
+	m := r.(map[string]interface{})
+	t.Logf("matched=%v counts=%v dominant=%v conclusion=%v", m["lines_matched"], m["counts"], m["dominant"], m["conclusion"])
+}
+
+func TestDiagDelta(t *testing.T) {
+	base := t.TempDir()
+	cur := t.TempDir()
+	sub := filepath.Join(base, "sub")
+	os.MkdirAll(sub, 0755)
+
+	// modified: same path, different content
+	os.WriteFile(filepath.Join(base, "a.txt"), []byte("hello"), 0644)
+	os.WriteFile(filepath.Join(cur, "a.txt"), []byte("world!"), 0644)
+	// created
+	os.WriteFile(filepath.Join(cur, "b.txt"), []byte("new"), 0644)
+	// deleted
+	os.WriteFile(filepath.Join(base, "gone.txt"), []byte("bye"), 0644)
+	// unchanged
+	os.WriteFile(filepath.Join(base, "same.txt"), []byte("x"), 0644)
+	os.WriteFile(filepath.Join(cur, "same.txt"), []byte("x"), 0644)
+
+	p := &Plugin{name: "recoverydiag"}
+	r, err := p.handleDelta(map[string]interface{}{"baseline_dir": base, "current_dir": cur})
+	if err != nil {
+		t.Fatalf("handleDelta: %v", err)
+	}
+	m := r.(map[string]interface{})
+	sum := m["summary"].(map[string]int)
+	t.Logf("summary=%v total=%v", sum, m["total_diff"])
+	if sum["created"] != 1 || sum["deleted"] != 1 || sum["modified"] != 1 {
+		t.Errorf("summary = %v, want modified=1 created=1 deleted=1", sum)
+	}
+}
+
+func TestDiagLoc(t *testing.T) {
+	p := &Plugin{name: "recoverydiag"}
+	r, _ := p.handleLoc(map[string]interface{}{
+		"triage":   map[string]interface{}{"class": "process_death", "verdict": "down"},
+		"db":       map[string]interface{}{"verdict": "ok"},
+		"log_scan": map[string]interface{}{"dominant": "panic"},
+		"delta":    map[string]interface{}{"summary": map[string]interface{}{"created": 0, "modified": 0, "deleted": 0}},
+	})
+	m := r.(map[string]interface{})
+	// 经 JSON 往返，模拟内核把子结论以 JSON 传给 diag_loc 的真实路径
+	raw, _ := json.Marshal(m)
+	var dec map[string]interface{}
+	json.Unmarshal(raw, &dec)
+	hs := dec["ranked_hypotheses"].([]interface{})
+	if len(hs) == 0 {
+		t.Fatal("no hypotheses")
+	}
+	top := hs[0].(map[string]interface{})
+	t.Logf("top cause=%v conf=%v rec=%v", top["cause"], top["confidence"], top["recommendation"])
+	if top["cause"] != "code_panic_loop" {
+		t.Errorf("expected code_panic_loop, got %v", top["cause"])
+	}
+}
+
+func TestDiagLocPersist(t *testing.T) {
+	kb := filepath.Join(t.TempDir(), "recovery_kb")
+	p := &Plugin{name: "recoverydiag", dataDir: filepath.Dir(kb)}
+	args := map[string]interface{}{
+		"persist":  true,
+		"triage":   map[string]interface{}{"class": "process_death", "verdict": "down"},
+		"db":       map[string]interface{}{"verdict": "ok"},
+		"log_scan": map[string]interface{}{"dominant": "panic"},
+		"delta":    map[string]interface{}{"summary": map[string]interface{}{"created": 0, "modified": 0, "deleted": 0}},
+	}
+	if _, err := p.handleLoc(args); err != nil {
+		t.Fatalf("handleLoc: %v", err)
+	}
+	entries, err := os.ReadDir(kb)
+	if err != nil || len(entries) == 0 {
+		t.Fatalf("expected persisted diag json, got err=%v entries=%v", err, entries)
+	}
+	data, _ := os.ReadFile(filepath.Join(kb, entries[0].Name()))
+	if !strings.Contains(string(data), `"cause"`) {
+		t.Errorf("persisted file missing cause field: %s", data)
+	}
+}

example/recoverydiag/plg.json

@@ -0,0 +1,21 @@
+{
+  "name": "recoverydiag",
+  "name_zh": "恢复诊断",
+  "name_en": "Recovery Diagnostics",
+  "version": "0.2.0",
+  "description": "快速检查/崩溃取证工具集：diag_triage（退出码/信号/存活粗分）、diag_db（config.db 完整性 + LLM 源解析校验）、diag_log_scan（日志签名命中）、diag_delta（last-good 快照 vs 现状 diff）、diag_loc（正交综合定位）。全部返回结论而非原文，确定性、不消耗 LLM token，供 guard / failback 恢复决策使用。",
+  "author": "HomeAgent",
+  "entry": "plugin.so",
+  "tags": [
+    "diag",
+    "recovery",
+    "diagnostics",
+    "triage",
+    "failback"
+  ],
+  "targets": "linux/amd64",
+  "outdir": "dist",
+  "bundle": true,
+  "replaces": {},
+  "source_dirs": []
+}