feat: v4.2 智能进化 — 技能自动生成 + 用户画像 + 人格模板

新增功能：

1. 技能自动生成系统 (Skill Loop)
   - 新增 skills 表：id/name/description/trigger_keywords/tool_chain/success_count/fail_count
   - skill-manager.ts: 从成功工具调用链自动提取可复用技能
   - 关键词匹配 + 成功率加权的技能检索
   - 匹配到的技能自动注入 system prompt（含工具链步骤和成功率）
   - Agent Loop 结束后自动提取，开始前自动匹配注入
   - DB/IPC/Preload 全链路支持

2. 用户画像模型
   - 自动从对话中推断技术栈（14 种技术关键词检测）
   - 画像存储在 settings.user_profile
   - 自动注入 system prompt（技术栈/角色/风格）
   - 随使用不断积累完善

3. 人格模板切换（6 种预设）
   - 🤖 通用助手（默认，温度跟随设置）
   - 💻 编程助手（温度 0.3，注重代码质量）
   - ✍️ 写作助手（温度 0.8，注重文采流畅）
   - 📊 数据分析（温度 0.2，注重精确逻辑）
   - 🌐 翻译助手（温度 0.4，注重信达雅）
   - 🔍 代码审查（温度 0.3，注重安全性能）
   - 设置面板 3×2 网格按钮，点击切换 + 自动调整温度

修改文件：9 个已有 + 1 个新建（skill-manager.ts）

src/main/db/sqlite.ts

@@ -203,6 +203,22 @@ export async function initDatabase(): Promise<SQL.Database> {
       FOREIGN KEY (session_id) REFERENCES sessions(id) ON DELETE CASCADE
     );
     CREATE INDEX IF NOT EXISTS idx_traces_session ON traces(session_id, created_at);
+
+    -- v4.2 技能表（自动从成功工具调用链提取）
+    CREATE TABLE IF NOT EXISTS skills (
+      id TEXT PRIMARY KEY,
+      name TEXT NOT NULL,
+      description TEXT NOT NULL,
+      trigger_keywords TEXT,
+      tool_chain TEXT NOT NULL,
+      success_count INTEGER DEFAULT 0,
+      fail_count INTEGER DEFAULT 0,
+      avg_duration_ms INTEGER DEFAULT 0,
+      created_at INTEGER NOT NULL,
+      updated_at INTEGER NOT NULL,
+      last_used_at INTEGER
+    );
+    CREATE INDEX IF NOT EXISTS idx_skills_updated ON skills(updated_at DESC);
   `);
 
   // 尝试创建 FTS5 全文搜索（可选，sql.js 默认 WASM 可能不包含 FTS5）
@@ -286,6 +302,21 @@ export interface ToolCallRow {
   created_at: number;
 }
 
+// v4.2
+export interface SkillRow {
+  id: string;
+  name: string;
+  description: string;
+  trigger_keywords: string | null;
+  tool_chain: string;
+  success_count: number;
+  fail_count: number;
+  avg_duration_ms: number;
+  created_at: number;
+  updated_at: number;
+  last_used_at: number | null;
+}
+
 export interface TraceRow {
   id: string;
   session_id: string;
@@ -487,6 +518,65 @@ export function getTracesBySession(sessionId: string): TraceRow[] {
   return queryAll(getDb(), 'SELECT * FROM traces WHERE session_id = ? ORDER BY step_index ASC', [sessionId]) as unknown as TraceRow[];
 }
 
+// ─── Skills CRUD (v4.2) ───
+
+export function saveSkill(skill: SkillRow): string {
+  runExec(getDb(), `INSERT OR REPLACE INTO skills (id, name, description, trigger_keywords, tool_chain, success_count, fail_count, avg_duration_ms, created_at, updated_at, last_used_at)
+    VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
+    [skill.id, skill.name, skill.description, skill.trigger_keywords, skill.tool_chain,
+     skill.success_count, skill.fail_count, skill.avg_duration_ms,
+     skill.created_at, skill.updated_at, skill.last_used_at]
+  );
+  persist();
+  return skill.id;
+}
+
+export function getSkill(id: string): SkillRow | null {
+  return queryOne(getDb(), 'SELECT * FROM skills WHERE id = ?', [id]) as unknown as SkillRow | null;
+}
+
+export function getAllSkills(): SkillRow[] {
+  return queryAll(getDb(), 'SELECT * FROM skills ORDER BY success_count DESC, updated_at DESC') as unknown as SkillRow[];
+}
+
+export function deleteSkill(id: string): void {
+  runExec(getDb(), 'DELETE FROM skills WHERE id = ?', [id]);
+  persist();
+}
+
+export function clearAllSkills(): void {
+  getDb().run('DELETE FROM skills');
+  persist();
+}
+
+export function searchSkills(keywords: string, limit = 5): SkillRow[] {
+  const likeQ = `%${keywords.replace(/[^\w\u4e00-\u9fff]/g, '%')}%`;
+  return queryAll(getDb(), `
+    SELECT * FROM skills
+    WHERE trigger_keywords LIKE ? OR name LIKE ? OR description LIKE ?
+    ORDER BY success_count DESC, updated_at DESC
+    LIMIT ?
+  `, [likeQ, likeQ, likeQ, limit]) as unknown as SkillRow[];
+}
+
+export function incrementSkillUsage(id: string, success: boolean, durationMs: number): void {
+  const d = getDb();
+  const skill = queryOne(d, 'SELECT success_count, fail_count, avg_duration_ms FROM skills WHERE id = ?', [id]) as any;
+  if (!skill) return;
+
+  const newSuccess = success ? skill.success_count + 1 : skill.success_count;
+  const newFail = success ? skill.fail_count : skill.fail_count + 1;
+  const totalUses = newSuccess + newFail;
+  // 指数移动平均
+  const alpha = 0.3;
+  const newAvg = Math.round(alpha * durationMs + (1 - alpha) * (skill.avg_duration_ms || durationMs));
+
+  runExec(d, `UPDATE skills SET success_count = ?, fail_count = ?, avg_duration_ms = ?, updated_at = ?, last_used_at = ? WHERE id = ?`,
+    [newSuccess, newFail, newAvg, Date.now(), Date.now(), id]
+  );
+  persist();
+}
+
 // ─── Export/Import ───
 
 export interface ExportData {