fix: 优先审批 + 首用户隔离 + 审批DB闭环 + memo错误

1. (High) 内置工具先审批再执行 — is_builtin 检查优先，
   High 风险通过 builtin_approve 后再调用 BuiltinRegistry
2. (High) 首用户 current_user_id — 移除 !is_empty() 守卫
3. (Medium) 审批 DB 状态闭环 — 取消/错误时按 user_id 更新最近 pending
4. (Medium) manage_memos 写入失败 — .ok() → 完整错误返回

src/main.rs

@@ -371,20 +371,22 @@ async fn cmd_listen(
                     cp.get("name").and_then(|v| v.as_str()).map(|s| s.to_string()).unwrap_or_default()
                 } else { n.clone() };
 
-                // 内置工具
-                if let Some(mut result) = tools::builtin::BuiltinRegistry::execute(&target_name, &args).await {
+                // 内置工具（高风险先审批再执行）
+                if tools::builtin::BuiltinRegistry::is_builtin(&target_name) {
                     if tools::builtin::BuiltinRegistry::is_high_risk(&target_name) {
                         let mut ctx = ExecutionContext::new(&user_id);
                         ctx = ctx.with_approval(approval.clone());
-                        ctx = ctx.with_wechat(send);
+                        ctx = ctx.with_wechat(send.clone());
                         let approved = builtin_approve(&ctx, &target_name).await;
                         match approved {
-                            Ok(true) => return Ok(result.output),
+                            Ok(true) => {},
                             Ok(false) => return Ok(SkillResult::rejected(&target_name).output),
                             Err(e) => return Ok(e),
                         }
                     }
-                    return Ok(result.output);
+                    if let Some(result) = tools::builtin::BuiltinRegistry::execute(&target_name, &args).await {
+                        return Ok(result.output);
+                    }
                 }
 
                 // 回退到外部 SkillRegistry
@@ -539,7 +541,7 @@ async fn listen_loop(
                     // 用户切换：清空上下文，加载新用户历史
                     {
                         let mut last_user = last_user_id.lock().await;
-                        if *last_user != from.to_string() && !last_user.is_empty() {
+                        if *last_user != *from {
                             info!("用户切换: {} → {}", *last_user, from);
                             if let Some(conv) = &conversation {
                                 let session = conv.session();

src/tools/approval.rs

@@ -126,12 +126,12 @@ impl ApprovalManager {
                 ApprovalDecision::Approved => "approved",
                 _ => "rejected",
             };
+            // 按 user_id + 最近 pending 记录更新
             let _ = sqlx::query(
-                "UPDATE pending_approvals SET status = $1, consumed_at = NOW() WHERE user_id = $2 AND code_hash = $3 AND status = 'pending'",
+                "UPDATE pending_approvals SET status = $1, consumed_at = NOW() WHERE user_id = $2 AND status = 'pending' ORDER BY created_at DESC LIMIT 1",
             )
             .bind(status)
             .bind(user_id)
-            .bind(&format!("{:x}", Sha256::digest(reply.as_bytes())))
             .execute(pool.as_ref())
             .await;
         }

src/tools/builtin.rs

@@ -36,6 +36,10 @@ impl BuiltinRegistry {
     pub fn is_high_risk(name: &str) -> bool {
         Self::specs().iter().any(|s| s.name == name && s.risk_level == RiskLevel::High)
     }
+
+    pub fn is_builtin(name: &str) -> bool {
+        Self::specs().iter().any(|s| s.name == name)
+    }
 }
 
 fn execute_datetime() -> SkillResult {
@@ -64,7 +68,9 @@ async fn handle_memos(args_json: &str) -> SkillResult {
                 "id": next_id, "content": content,
                 "created_at": Local::now().format("%Y-%m-%d %H:%M").to_string()
             }));
-            std::fs::write(path, serde_json::to_string_pretty(&data).unwrap()).ok();
+            if let Err(e) = std::fs::write(path, serde_json::to_string_pretty(&data).unwrap()) {
+                return SkillResult::error(format!("写入备忘录失败: {}", e));
+            }
             SkillResult::ok(format!("已添加备忘录 #{}", next_id))
         }
         "list" => {
@@ -80,7 +86,9 @@ async fn handle_memos(args_json: &str) -> SkillResult {
             let before = data.len();
             data.retain(|m| m.get("id").and_then(|v| v.as_i64()) != Some(id));
             if data.len() == before { return SkillResult::error(format!("未找到备忘录 #{}", id)); }
-            std::fs::write(path, serde_json::to_string_pretty(&data).unwrap()).ok();
+            if let Err(e) = std::fs::write(path, serde_json::to_string_pretty(&data).unwrap()) {
+                return SkillResult::error(format!("写入备忘录失败: {}", e));
+            }
             SkillResult::ok(format!("已删除备忘录 #{}", id))
         }
         _ => SkillResult::error("未知操作，支持: add, list, delete"),