fix: resolve 10 code review issues

High priority:
- Fix concurrent race condition for view_count/like_count (atomic update)
- Add route request ID tracking to prevent race conditions
- Filter get_joke by status=approved (no pending content leak)
- Add error feedback for like button

Performance:
- Optimize random joke query (avoid full table sort)
- Limit page_size max to 100 (DoS prevention)

Medium:
- Add localStorage quota error handling
- Handle empty AI response gracefully
- Fix generate content title extraction

Low:
- Add rejected_jokes to stats API
- Update dashboard to show rejected count

crawler/site_finder.py

@@ -0,0 +1,128 @@
+"""
+笑话站点发现工具。
+搜索 Bing 获取笑话聚合网站列表，保存到 JSON 文件。
+
+用法:
+  python crawler/site_finder.py
+  python crawler/site_finder.py --keywords "笑话大全,冷笑话" --output my_sites.json
+  python crawler/site_finder.py --no-headless
+"""
+import argparse
+import asyncio
+import json
+import os
+import sys
+from datetime import datetime
+
+if sys.platform == "win32":
+    import shutil
+    os.environ["PYTHONIOENCODING"] = "utf-8"
+    os.environ["TERM"] = "dumb"
+    try:
+        shutil.get_terminal_size()
+    except Exception:
+        pass
+
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+from crawler.crawler_service import CrawlerService
+
+
+def parse_args():
+    parser = argparse.ArgumentParser(description="笑话站点发现工具")
+    parser.add_argument(
+        "--keywords",
+        type=str,
+        default=os.getenv("CRAWL_KEYWORD", "笑话大全,搞笑段子,冷笑话,幽默笑话,爆笑笑话,笑话集锦"),
+        help="搜索关键词，逗号分隔",
+    )
+    parser.add_argument(
+        "--output",
+        type=str,
+        default="joke_sites.json",
+        help="输出 JSON 文件路径（默认: joke_sites.json）",
+    )
+    parser.add_argument(
+        "--max-sites",
+        type=int,
+        default=15,
+        help="最多保留几个站点（默认: 15）",
+    )
+    parser.add_argument(
+        "--no-headless",
+        action="store_true",
+        help="显示浏览器窗口",
+    )
+    return parser.parse_args()
+
+
+def load_existing_sites(path: str) -> list[dict]:
+    """加载已有站点列表"""
+    if os.path.exists(path):
+        try:
+            with open(path, "r", encoding="utf-8") as f:
+                return json.load(f)
+        except Exception:
+            pass
+    return []
+
+
+def save_sites(path: str, sites: list[dict]):
+    """保存站点列表到 JSON 文件"""
+    with open(path, "w", encoding="utf-8") as f:
+        json.dump(sites, f, ensure_ascii=False, indent=2)
+    print(f"\n[OK] 已保存 {len(sites)} 个站点到 {path}")
+
+
+def main():
+    args = parse_args()
+    headless = not args.no_headless
+    keywords = [k.strip() for k in args.keywords.split(",") if k.strip()]
+
+    print(f"=" * 50)
+    print(f"笑话站点发现工具")
+    print(f"搜索词: {keywords}")
+    print(f"最大站点数: {args.max_sites}")
+    print(f"输出文件: {args.output}")
+    print(f"浏览器: {'显示窗口' if not headless else '无头模式'}")
+    print(f"=" * 50)
+
+    # 加载已存在的站点（保留已有编号）
+    existing = load_existing_sites(args.output)
+    existing_domains = {s["domain"] for s in existing}
+    next_id = max([s["id"] for s in existing], default=0) + 1
+    print(f"[*] 已有 {len(existing)} 个站点记录，新编号从 {next_id} 开始")
+
+    async def run():
+        nonlocal next_id
+        crawler = CrawlerService(headless=headless)
+        try:
+            new_sites = await crawler.search_joke_sites(keywords, max_results=args.max_sites)
+        finally:
+            await crawler.close()
+
+        # 合并新旧站点（去重）
+        added = 0
+        for site in new_sites:
+            domain = site["domain"]
+            if domain not in existing_domains:
+                site["id"] = next_id
+                site["found_at"] = datetime.now().isoformat(timespec="seconds")
+                existing.append(site)
+                existing_domains.add(domain)
+                next_id += 1
+                added += 1
+                print(f"  [+] 新增 #{site['id']}: {site['domain']} — {site['title'][:40]}")
+
+        save_sites(args.output, existing)
+
+        if existing:
+            print(f"\n站点列表：")
+            for s in existing:
+                print(f"  #{s['id']:2d}  {s['domain']:30s} {s['title'][:35]}")
+
+    asyncio.run(run())
+
+
+if __name__ == "__main__":
+    main()