fix: Markdown开关改用data属性存储内容，修复切换失效问题

- 数据列表中未读数据（views=0）显示特殊样式（黄色背景+红色边框+红点标记）
- 左侧类别显示未读数量（红色badge）
- API返回unread和unread_by_type统计数据

xian_favor/db.py

@@ -187,6 +187,31 @@ class Database:
             cursor.execute("CREATE INDEX IF NOT EXISTS idx_folders_type ON folders(type)")
             cursor.execute("CREATE INDEX IF NOT EXISTS idx_folders_parent ON folders(parent_id)")
             
+            # 检查并添加 is_pinned 字段（置顶功能，兼容旧数据库）
+            try:
+                cursor.execute("SELECT is_pinned FROM items LIMIT 1")
+            except sqlite3.OperationalError:
+                cursor.execute("ALTER TABLE items ADD COLUMN is_pinned INTEGER DEFAULT 0")
+            
+            # 创建 is_pinned 索引
+            cursor.execute("CREATE INDEX IF NOT EXISTS idx_items_pinned ON items(is_pinned)")
+            
+            # 待办事务表（关联到文本类别的items）
+            cursor.execute("""
+                CREATE TABLE IF NOT EXISTS todo_events (
+                    id INTEGER PRIMARY KEY AUTOINCREMENT,
+                    item_id INTEGER NOT NULL,
+                    content TEXT NOT NULL,
+                    remaining_days INTEGER DEFAULT 1,
+                    is_completed INTEGER DEFAULT 0,
+                    created_at TEXT NOT NULL,
+                    updated_at TEXT NOT NULL,
+                    FOREIGN KEY (item_id) REFERENCES items(id) ON DELETE CASCADE
+                )
+            """)
+            cursor.execute("CREATE INDEX IF NOT EXISTS idx_todo_events_item ON todo_events(item_id)")
+            cursor.execute("CREATE INDEX IF NOT EXISTS idx_todo_events_created ON todo_events(created_at)")
+            
             conn.commit()
     
     # ============ Item 操作 ============
@@ -289,18 +314,16 @@ class Database:
             if conditions:
                 query += " WHERE " + " AND ".join(conditions)
             
-            # 排序逻辑
+            # 排序逻辑：置顶 > 关注 > 创建时间
             if sort_by == 'updated_at':
                 order_field = 'i.updated_at'
             elif sort_by == 'created_at':
                 order_field = 'i.created_at'
             else:
-                # 默认：重点关注优先 + 创建时间降序
+                # 默认：置顶优先 + 关注优先 + 创建时间降序
                 order_field = 'i.created_at'
             
-            order_dir = 'DESC' if (sort_order == 'asc' or sort_order is None) else 'ASC'
-            # 这里反转逻辑：用户选择"降序"时用DESC，选择"升序"时用ASC
-            
+            # 确定排序方向
             if sort_order == 'asc':
                 order_dir = 'ASC'
             elif sort_order == 'desc':
@@ -308,12 +331,12 @@ class Database:
             else:
                 order_dir = 'DESC'  # 默认降序
             
-            # 如果有指定排序字段，按该字段排序；否则默认重点关注优先
+            # 如果有指定排序字段，按该字段排序，但置顶始终优先
             if sort_by:
-                query += f" ORDER BY {order_field} {order_dir} LIMIT ? OFFSET ?"
+                query += f" ORDER BY i.is_pinned DESC, {order_field} {order_dir} LIMIT ? OFFSET ?"
             else:
-                # 默认：重点关注优先，然后创建时间降序
-                query += f" ORDER BY i.is_starred DESC, i.created_at DESC LIMIT ? OFFSET ?"
+                # 默认：置顶 > 关注 > 创建时间降序
+                query += f" ORDER BY i.is_pinned DESC, i.is_starred DESC, i.created_at DESC LIMIT ? OFFSET ?"
             params.extend([limit, offset])
             
             cursor.execute(query, params)
@@ -375,7 +398,7 @@ class Database:
     
     def update_item(self, item_id: int, **kwargs) -> bool:
         """更新条目"""
-        allowed_fields = ['type', 'title', 'content', 'url', 'source', 'status', 'priority', 'due_date', 'note', 'is_starred']
+        allowed_fields = ['type', 'title', 'content', 'url', 'source', 'status', 'priority', 'due_date', 'note', 'is_starred', 'folder_id']
         update_fields = {k: v for k, v in kwargs.items() if k in allowed_fields}
         
         # 只有 tags 变化也算有效更新
@@ -501,6 +524,31 @@ class Database:
             conn.commit()
             return cursor.rowcount > 0
     
+    def toggle_pin(self, item_id: int) -> bool:
+        """切换置顶状态"""
+        with self.get_conn() as conn:
+            cursor = conn.cursor()
+            # 先获取当前状态
+            cursor.execute("SELECT is_pinned FROM items WHERE id = ?", (item_id,))
+            row = cursor.fetchone()
+            if not row:
+                return False
+            
+            new_status = 0 if row['is_pinned'] else 1
+            now = datetime.now().isoformat()
+            cursor.execute("UPDATE items SET is_pinned = ?, updated_at = ? WHERE id = ?", (new_status, now, item_id))
+            conn.commit()
+            return True
+    
+    def set_pin(self, item_id: int, pinned: bool = True) -> bool:
+        """设置置顶状态"""
+        with self.get_conn() as conn:
+            cursor = conn.cursor()
+            now = datetime.now().isoformat()
+            cursor.execute("UPDATE items SET is_pinned = ?, updated_at = ? WHERE id = ?", (1 if pinned else 0, now, item_id))
+            conn.commit()
+            return cursor.rowcount > 0
+    
     def increment_views(self, item_id: int) -> bool:
         """增加阅读数"""
         with self.get_conn() as conn:
@@ -903,15 +951,23 @@ class Database:
             stats = {}
             
             # 总数
-            cursor.execute("SELECT COUNT(*) as count FROM items")
+            cursor.execute("SELECT COUNT(*) as count FROM items WHERE is_deleted = 0")
             stats['total'] = cursor.fetchone()['count']
             
             # 按类型统计
-            cursor.execute("SELECT type, COUNT(*) as count FROM items GROUP BY type")
+            cursor.execute("SELECT type, COUNT(*) as count FROM items WHERE is_deleted = 0 GROUP BY type")
             stats['by_type'] = {row['type']: row['count'] for row in cursor.fetchall()}
             
+            # 未读数量统计（views = 0）
+            cursor.execute("SELECT COUNT(*) as count FROM items WHERE is_deleted = 0 AND (views IS NULL OR views = 0)")
+            stats['unread'] = cursor.fetchone()['count']
+            
+            # 按类型统计未读数量
+            cursor.execute("SELECT type, COUNT(*) as count FROM items WHERE is_deleted = 0 AND (views IS NULL OR views = 0) GROUP BY type")
+            stats['unread_by_type'] = {row['type']: row['count'] for row in cursor.fetchall()}
+            
             # 待办状态统计
-            cursor.execute("SELECT status, COUNT(*) as count FROM items WHERE type = 'todo' GROUP BY status")
+            cursor.execute("SELECT status, COUNT(*) as count FROM items WHERE type = 'todo' AND is_deleted = 0 GROUP BY status")
             stats['todo_status'] = {row['status']: row['count'] for row in cursor.fetchall()}
             
             # 标签数
@@ -1166,6 +1222,93 @@ class Database:
                 # 删除
                 self.delete_backup(backup['name'])
 
+    # ============ Todo Events 待办事务操作 ============
+    
+    def create_todo_event(self, item_id: int, content: str, remaining_days: int = 1) -> int:
+        """创建待办事务"""
+        self._ensure_init()
+        now = datetime.now().isoformat()
+        
+        with self.get_conn() as conn:
+            cursor = conn.cursor()
+            cursor.execute("""
+                INSERT INTO todo_events (item_id, content, remaining_days, is_completed, created_at, updated_at)
+                VALUES (?, ?, ?, 0, ?, ?)
+            """, (item_id, content, remaining_days, now, now))
+            conn.commit()
+            return cursor.lastrowid
+    
+    def list_todo_events(self, item_id: int, limit: int = 10, offset: int = 0) -> List[Dict[str, Any]]:
+        """列出待办事务（按时间倒序）"""
+        self._ensure_init()
+        
+        with self.get_conn() as conn:
+            cursor = conn.cursor()
+            cursor.execute("""
+                SELECT * FROM todo_events 
+                WHERE item_id = ? 
+                ORDER BY created_at DESC 
+                LIMIT ? OFFSET ?
+            """, (item_id, limit, offset))
+            rows = cursor.fetchall()
+            return [dict(row) for row in rows]
+    
+    def count_todo_events(self, item_id: int) -> int:
+        """计算待办事务总数"""
+        self._ensure_init()
+        
+        with self.get_conn() as conn:
+            cursor = conn.cursor()
+            cursor.execute("SELECT COUNT(*) as count FROM todo_events WHERE item_id = ?", (item_id,))
+            return cursor.fetchone()['count']
+    
+    def get_todo_event(self, event_id: int) -> Optional[Dict[str, Any]]:
+        """获取单个待办事务"""
+        self._ensure_init()
+        
+        with self.get_conn() as conn:
+            cursor = conn.cursor()
+            cursor.execute("SELECT * FROM todo_events WHERE id = ?", (event_id,))
+            row = cursor.fetchone()
+            return dict(row) if row else None
+    
+    def update_todo_event(self, event_id: int, content: str = None, remaining_days: int = None, is_completed: bool = None) -> bool:
+        """更新待办事务"""
+        self._ensure_init()
+        now = datetime.now().isoformat()
+        
+        with self.get_conn() as conn:
+            cursor = conn.cursor()
+            
+            # 获取当前数据
+            cursor.execute("SELECT * FROM todo_events WHERE id = ?", (event_id,))
+            row = cursor.fetchone()
+            if not row:
+                return False
+            
+            # 更新字段
+            new_content = content if content is not None else row['content']
+            new_days = remaining_days if remaining_days is not None else row['remaining_days']
+            new_completed = 1 if is_completed is True else (0 if is_completed is False else row['is_completed'])
+            
+            cursor.execute("""
+                UPDATE todo_events 
+                SET content = ?, remaining_days = ?, is_completed = ?, updated_at = ?
+                WHERE id = ?
+            """, (new_content, new_days, new_completed, now, event_id))
+            conn.commit()
+            return True
+    
+    def delete_todo_event(self, event_id: int) -> bool:
+        """删除待办事务"""
+        self._ensure_init()
+        
+        with self.get_conn() as conn:
+            cursor = conn.cursor()
+            cursor.execute("DELETE FROM todo_events WHERE id = ?", (event_id,))
+            conn.commit()
+            return cursor.rowcount > 0
+
 
 # 全局数据库实例
 db = Database()