feat(obsidian-kb): 实现短链接解析功能

- 新增 shortlink_resolver.py 模块
  * 检测 B站短链接（b23.tv）和其他短链接服务
  * 提供友好的用户引导信息
  * 支持 Playwright 浏览器自动化解析（可选）

- 集成到 handler.py
  * 短链接自动检测和提示
  * 智能区分短链接和完整 URL

- 更新 add_video.py
  * 支持短链接解析
  * 添加 --playwright 参数启用浏览器解析

- 新增 test_shortlink.py 测试脚本
  * 测试单个短链接检测
  * 测试多个短链接检测
  * 测试混合内容场景
  * 所有测试通过

- 更新文档
  * SKILL.md: 添加短链接说明
  * AUTO_TRIGGER.md: 添加短链接章节
  * obsidian-kb-improvements.md: 标记任务2为已完成

功能特点：
- 方案A（用户引导）：已实现并作为默认行为
- 方案B（浏览器自动化）：提供 PlaywrightResolver 类，可选使用
- 方案C（代理池）：未实现（复杂度高，收益低）

验收标准达成：
✅ 短链接能够友好处理（显示引导信息）
✅ 用户不会感到困惑
✅ 支持 b23.tv 和其他短链接服务（检测）
✅ 集成到 handler.py
✅ 测试各种短链接场景

skills/obsidian-kb/add_video.py

@@ -13,16 +13,22 @@ sys.path.insert(0, os.path.join(os.path.dirname(os.path.abspath(__file__)), 'src
 from sources.bilibili import BilibiliAdapter
 from models import Content, ContentStatus
 from storage import Storage
+from shortlink_resolver import (
+    ShortLinkResolver,
+    PlaywrightResolver,
+    detect_and_format
+)
 
-def resolve_short_url(url: str) -> str:
+def resolve_short_url(url: str, try_playwright: bool = False) -> str:
     """
     解析短链接（如 b23.tv）到完整URL，或接受BV号
 
     Args:
         url: 可能是短链接的URL、完整URL或BV号
+        try_playwright: 是否尝试使用Playwright解析短链接
 
     Returns:
-        str: 完整URL或BV号
+        str: 完整URL或BV号，如果失败返回None
     """
     # 如果已经是完整URL，直接返回
     if 'bilibili.com/video/' in url:
@@ -33,23 +39,42 @@ def resolve_short_url(url: str) -> str:
         return url
 
     # 如果是短链接，尝试解析
-    if 'b23.tv' in url:
+    resolver = ShortLinkResolver()
+
+    if resolver.is_bilibili_short_link(url):
         print(f"  ⚠️  检测到短链接 {url}")
-        print(f"  💡 B站对短链接有反爬虫保护，请提供:")
-        print(f"     1. 完整URL: https://www.bilibili.com/video/BVxxxxx")
-        print(f"     2. 或BV号: BVxxxxx")
-        print(f"\n  提示: 可以在浏览器打开短链接，从地址栏复制完整URL")
+
+        # 尝试使用Playwright解析（如果启用）
+        if try_playwright:
+            print(f"  🔄 尝试使用浏览器解析...")
+            playwright_resolver = PlaywrightResolver(headless=True)
+
+            try:
+                resolved_url = playwright_resolver.resolve_bilibili_short(url)
+                if resolved_url:
+                    print(f"  ✅ 解析成功: {resolved_url}")
+                    return resolved_url
+                else:
+                    print(f"  ❌ 浏览器解析失败")
+            except Exception as e:
+                print(f"  ❌ Playwright不可用或解析失败: {e}")
+
+        # 显示用户引导
+        print("")
+        print(resolver.format_short_link_help(url))
+        print("")
         return None
 
     # 默认返回原URL
     return url
 
-def add_video_to_inbox(url: str) -> str:
+def add_video_to_inbox(url: str, try_playwright: bool = False) -> str:
     """
     添加B站视频到收件箱
 
     Args:
         url: B站视频URL
+        try_playwright: 是否尝试使用Playwright解析短链接
 
     Returns:
         str: Content ID
@@ -57,7 +82,7 @@ def add_video_to_inbox(url: str) -> str:
     print(f"📥 正在处理视频: {url}")
 
     # 解析短链接
-    resolved_url = resolve_short_url(url)
+    resolved_url = resolve_short_url(url, try_playwright=try_playwright)
     if resolved_url is None:
         return None
 
@@ -104,8 +129,17 @@ def add_video_to_inbox(url: str) -> str:
 if __name__ == '__main__':
     if len(sys.argv) < 2:
         print("用法: python3 add_video.py <B站视频URL>")
-        print("示例: python3 add_video.py https://b23.tv/oLBZZfK")
+        print("示例:")
+        print("  python3 add_video.py https://www.bilibili.com/video/BV1xx411c7mD")
+        print("  python3 add_video.py BV1xx411c7mD")
+        print("  python3 add_video.py https://b23.tv/oLBZZfK")
+        print("\n选项:")
+        print("  --playwright  尝试使用浏览器解析短链接")
         sys.exit(1)
 
     url = sys.argv[1]
-    add_video_to_inbox(url)
+    try_playwright = '--playwright' in sys.argv
+    if try_playwright and url == '--playwright' and len(sys.argv) > 2:
+        url = sys.argv[2]
+
+    add_video_to_inbox(url, try_playwright=try_playwright)