feat(07-03): implement login CLI subcommand

- Add login_command function with QR code login, cookie import, and status check
- Add login subcommand with --import-cookie and --status options
- Update CLI help text with login examples
- Fix mock paths in tests to match actual import locations

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

kb_workflow/kb_workflow.py

@@ -11,6 +11,9 @@ KB Workflow - Knowledge Base Workflow Orchestrator
 使用方式:
     python kb_workflow.py process "https://www.bilibili.com/video/BVxxx"
     python kb_workflow.py process "https://..." -o /path/to/output
+    python kb_workflow.py login                    # QR code login
+    python kb_workflow.py login --import-cookie cookies.json
+    python kb_workflow.py login --status
 """
 
 import argparse
@@ -102,6 +105,68 @@ def process_command(
         }
 
 
+def login_command(
+    import_cookie: Optional[str] = None,
+    status: bool = False
+) -> Dict[str, Any]:
+    """Execute login command
+
+    Args:
+        import_cookie: Path to JSON cookie file
+        status: Check current cookie status
+
+    Returns:
+        Dictionary with login result
+    """
+    try:
+        from kb_workflow.auth import ZhihuLogin
+        from kb_workflow.auth.cookie_manager import CookieManager, parse_json_cookies
+        from kb_workflow.pipeline.config import get_settings
+
+        settings = get_settings()
+        manager = CookieManager()
+
+        # Check Cookie status
+        if status:
+            current_cookie = settings.zhihu_cookie.get_secret_value()
+            if not current_cookie:
+                return {"valid": False, "reason": "No cookie found in ~/.kb_env"}
+
+            async def check_status():
+                login = ZhihuLogin(intermediate_path=settings.intermediate_path)
+                try:
+                    login.browser = login.browser or type('obj', (object,), {
+                        'browser': None,
+                        'page': None,
+                        'start': lambda cookie=None: None,
+                        'close': lambda: None
+                    })()
+                    login.browser.start(cookie=current_cookie)
+                    return await login.validate_cookie(current_cookie)
+                finally:
+                    if login.browser and hasattr(login.browser, 'close'):
+                        login.browser.close()
+
+            result = asyncio.run(check_status())
+            return result.model_dump()
+
+        # Import Cookie
+        if import_cookie:
+            cookie_str = parse_json_cookies(import_cookie)
+            manager.save_cookie(cookie_str)
+            return {"success": True, "message": f"Cookie imported from {import_cookie}"}
+
+        # QR code login (synchronous method)
+        login = ZhihuLogin(intermediate_path=settings.intermediate_path)
+        result = login.login_by_qrcode()
+        if result.success and result.cookie_str:
+            manager.save_cookie(result.cookie_str)
+        return result.model_dump()
+
+    except Exception as e:
+        return {"success": False, "error": str(e)}
+
+
 def main():
     """CLI入口 - 用于命令行调用"""
     parser = argparse.ArgumentParser(
@@ -117,6 +182,15 @@ def main():
 
   # 强制重新执行（忽略已完成状态）
   python kb_workflow.py process "https://..." --no-skip
+
+  # 知乎登录 (二维码扫码)
+  python kb_workflow.py login
+
+  # 导入 Cookie
+  python kb_workflow.py login --import-cookie cookies.json
+
+  # 检查 Cookie 状态
+  python kb_workflow.py login --status
         '''
     )
 
@@ -132,6 +206,13 @@ def main():
     process_parser.add_argument('--no-skip', action='store_false', dest='skip_completed',
                                 help='Re-run all steps')
 
+    # Login subcommand
+    login_parser = subparsers.add_parser('login', help='Zhihu login authentication')
+    login_parser.add_argument('--import-cookie', '-i', type=str,
+                              help='Import cookie from JSON file')
+    login_parser.add_argument('--status', action='store_true',
+                              help='Check current cookie status')
+
     args = parser.parse_args()
 
     # Handle process subcommand
@@ -142,6 +223,13 @@ def main():
             skip_completed=args.skip_completed
         )
         print(json.dumps(result, ensure_ascii=False, indent=2))
+    # Handle login subcommand
+    elif args.command == 'login':
+        result = login_command(
+            import_cookie=args.import_cookie,
+            status=args.status
+        )
+        print(json.dumps(result, ensure_ascii=False, indent=2))
     else:
         parser.print_help()