feat: init rssKeeper - RSS 抓取、管理与检索系统

完整功能包括:
- FastAPI 后端 + SQLite + FTS5 全文搜索
- RSS 源管理、自动发现、OPML 导入导出
- 文章抓取、去重、分类、全文检索
- RSS 源健康度监控
- Vue 3 + Element Plus 暗色主题 Web UI
- 对外 REST API 供 AI 分析调用
- Docker + docker-compose 部署

backend/scheduler.py

@@ -0,0 +1,74 @@
+"""APScheduler 定时任务管理"""
+from apscheduler.schedulers.background import BackgroundScheduler
+from apscheduler.triggers.interval import IntervalTrigger
+from rss_fetcher import fetch_and_store_feed
+import config
+
+_scheduler = None
+
+
+def get_scheduler():
+    """获取或创建调度器实例"""
+    global _scheduler
+    if _scheduler is None:
+        _scheduler = BackgroundScheduler()
+    return _scheduler
+
+
+def add_feed_job(feed_id: int, interval_minutes: int):
+    """为指定 RSS 源添加定时抓取任务"""
+    scheduler = get_scheduler()
+    job_id = f"fetch_feed_{feed_id}"
+
+    # 确保间隔不低于最小值
+    interval = max(interval_minutes, config.MIN_FETCH_INTERVAL)
+
+    # 如果任务已存在则更新
+    existing = scheduler.get_job(job_id)
+    if existing:
+        existing.reschedule(trigger=IntervalTrigger(minutes=interval))
+        return
+
+    scheduler.add_job(
+        fetch_and_store_feed,
+        trigger=IntervalTrigger(minutes=interval),
+        id=job_id,
+        args=[feed_id],
+        replace_existing=True,
+        misfire_grace_time=300,  # 5分钟容错
+        coalesce=True,  # 合并错过的任务
+    )
+
+
+def remove_feed_job(feed_id: int):
+    """移除指定 RSS 源的定时任务"""
+    scheduler = get_scheduler()
+    job_id = f"fetch_feed_{feed_id}"
+    try:
+        scheduler.remove_job(job_id)
+    except Exception:
+        pass
+
+
+def start_scheduler():
+    """启动调度器"""
+    scheduler = get_scheduler()
+    if not scheduler.running:
+        scheduler.start()
+
+
+def stop_scheduler():
+    """停止调度器"""
+    global _scheduler
+    if _scheduler and _scheduler.running:
+        _scheduler.shutdown(wait=False)
+        _scheduler = None
+
+
+def init_feed_jobs(db):
+    """从数据库加载所有活跃 RSS 源并注册定时任务"""
+    from models import Feed
+    feeds = db.query(Feed).filter(Feed.is_active == True).all()
+    for feed in feeds:
+        add_feed_job(feed.id, feed.fetch_interval_minutes or config.DEFAULT_FETCH_INTERVAL)
+    start_scheduler()