- **Bootstrap IoC-based architecture with modular services.**

- **Implement `MlxModelService` for local LLM backend.**
- **Introduce `DatabaseService` for MySQL integration.**
- **Add `HistoryService` to manage conversation context.**
- **Set up CLI interface via `CliUiService`.**
- **Establish EventBus for token streaming.**
- **Include conversation repository for data persistence.**
- **Add environment-based configuration management.**
- **Draft IoC architectural plan.**

services/db/mysql_service.py

@@ -0,0 +1,63 @@
+from __future__ import annotations
+from typing import Any
+
+
+class DatabaseService:
+    """MySQL 연결을 캡슐화하는 서비스. 미설정 시 graceful skip."""
+
+    def __init__(self, host: str, port: int, db: str, user: str, password: str):
+        self._config = dict(host=host, port=port, db=db, user=user, passwd=password)
+        self._conn = None
+
+    def connect(self) -> None:
+        if not self._config["user"]:
+            return
+        try:
+            import pymysql
+            self._conn = pymysql.connect(**self._config)
+        except Exception as e:
+            print(f"[DB] 연결 실패 (선택적 기능): {e}")
+
+    def execute(self, sql: str, params: tuple = ()) -> list[dict[str, Any]]:
+        if self._conn is None:
+            return []
+        cursor = self._conn.cursor()
+        cursor.execute(sql, params)
+        columns = [d[0] for d in cursor.description or []]
+        return [dict(zip(columns, row)) for row in cursor.fetchall()]
+
+    def execute_write(self, sql: str, params: tuple = ()) -> int:
+        """INSERT/UPDATE/DELETE 실행 후 lastrowid 반환."""
+        if self._conn is None:
+            return 0
+        cursor = self._conn.cursor()
+        cursor.execute(sql, params)
+        self._conn.commit()
+        return cursor.lastrowid
+
+    def init_schema(self) -> None:
+        if self._conn is None:
+            return
+        cursor = self._conn.cursor()
+        cursor.execute("""
+            CREATE TABLE IF NOT EXISTS td_conversations (
+                id INT AUTO_INCREMENT PRIMARY KEY,
+                created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+            )
+        """)
+        cursor.execute("""
+            CREATE TABLE IF NOT EXISTS td_messages (
+                id INT AUTO_INCREMENT PRIMARY KEY,
+                conversation_id INT NOT NULL,
+                role VARCHAR(20) NOT NULL,
+                content TEXT NOT NULL,
+                created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+                FOREIGN KEY (conversation_id) REFERENCES td_conversations(id)
+            )
+        """)
+        self._conn.commit()
+
+    def close(self) -> None:
+        if self._conn:
+            self._conn.close()
+            self._conn = None