feat: add todos table to mofin_db + DB_PATH fix for self_todo_executor

mofin_db.py

@@ -409,6 +409,21 @@ def init_all_tables(conn: sqlite3.Connection):
             cache_json      TEXT,
             updated_at      TEXT DEFAULT (datetime('now','localtime'))
         );
+
+        -- Self-TODO 自动化任务表
+        CREATE TABLE IF NOT EXISTS todos (
+            id              INTEGER PRIMARY KEY AUTOINCREMENT,
+            title           TEXT NOT NULL,
+            description     TEXT,
+            status          TEXT DEFAULT 'pending',
+            priority        TEXT DEFAULT 'medium',
+            source          TEXT DEFAULT 'manual',
+            fix_action      TEXT,
+            retry_count     INTEGER DEFAULT 0,
+            note            TEXT,
+            created_at      TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+            updated_at      TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+        );
     """)
     conn.commit()