refactor: skill 脚本输出改为结构化 JSON

- query_weather: {location, now: {temp,text}, forecast: [{date,day,night,tempMin,tempMax}]}
- search_web: {query, answer, results: [{title,url,content}]}
- get_current_datetime: {datetime}
- list_scheduled_tasks: {tasks: [{name,description,enabled,command,...}]}
- manage_scheduled_task: {ok, action, name} / {error}

LLM 直接看到结构化数据，不再依赖脚本拼接的中文自然语言

resources/skills/list_scheduled_tasks/scripts/list.sh

@@ -1,27 +1,26 @@
 #!/bin/bash
-# 列出定时任务（从 PostgreSQL）
-set -e
-
+# 列出定时任务 → JSON 输出
 DB_URL="${DATABASE_URL}"
-if [ -z "$DB_URL" ]; then
-  echo "数据库未配置（DATABASE_URL）"
-  exit 0
-fi
+[ -z "$DB_URL" ] && echo '{"tasks":[],"error":"数据库未配置"}' && exit 0
 
-# 使用 psql 查询
 psql "$DB_URL" -t -A -F '|' -c "
-  SELECT name, description, enabled, next_run_at, interval_seconds
-  FROM scheduled_tasks
-  ORDER BY name
-" 2>/dev/null | while IFS='|' read -r name desc enabled next_run interval; do
-  if [ -n "$name" ]; then
-    echo "- $name${desc:+ ($desc)}"
-    echo "  启用: $enabled | 间隔: ${interval}s | 下次: ${next_run:-无}"
-  fi
-done
-
-# 检查是否有任何任务
-COUNT=$(psql "$DB_URL" -t -A -c "SELECT count(*) FROM scheduled_tasks" 2>/dev/null || echo "0")
-if [ "$COUNT" = "0" ] || [ -z "$COUNT" ]; then
-  echo "暂无定时任务"
-fi
+  SELECT jsonb_build_object(
+    'name', name,
+    'description', description,
+    'enabled', enabled,
+    'command', command,
+    'interval_seconds', interval_seconds,
+    'next_run_at', next_run_at
+  )
+  FROM scheduled_tasks ORDER BY name
+" 2>/dev/null | python3 -c "
+import sys, json
+tasks = []
+for line in sys.stdin:
+    line = line.strip()
+    if line:
+        try: tasks.append(json.loads(line))
+        except: pass
+print(json.dumps({'tasks': tasks}, ensure_ascii=False))
+"
+[ -z "$(psql "$DB_URL" -t -A -c "SELECT count(*) FROM scheduled_tasks" 2>/dev/null)" ] && echo '{"tasks":[]}'