feat: migrate core data stores to MySQL with compatibility fixes

db/designer_roster_db.py

@@ -17,6 +17,46 @@ _MYSQL_USER = os.getenv("MYSQL_USER", "root")
 _MYSQL_PASSWORD = os.getenv("MYSQL_PASSWORD", "")
 _MYSQL_DATABASE = os.getenv("MYSQL_DATABASE", "ai_cs")
 
+
+class _CompatResult:
+    def __init__(self, rows=None, rowcount: int = 0, lastrowid: int = 0):
+        self._rows = rows or []
+        self.rowcount = rowcount
+        self.lastrowid = lastrowid
+
+    def fetchall(self):
+        return self._rows
+
+    def fetchone(self):
+        return self._rows[0] if self._rows else None
+
+
+class _PyMySQLCompatConn:
+    def __init__(self, conn):
+        self._conn = conn
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc, tb):
+        if exc_type:
+            try:
+                self._conn.rollback()
+            except Exception:
+                pass
+        self._conn.close()
+
+    def execute(self, query: str, args=None):
+        cur = self._conn.cursor()
+        cur.execute(query, args or ())
+        rows = cur.fetchall() if cur.description else []
+        res = _CompatResult(rows=rows, rowcount=cur.rowcount, lastrowid=getattr(cur, "lastrowid", 0))
+        cur.close()
+        return res
+
+    def commit(self):
+        self._conn.commit()
+
 def _is_mysql() -> bool:
     return _DB_TYPE in ("mysql", "mariadb")
 
@@ -27,7 +67,7 @@ def _sql(query: str) -> str:
 def _get_conn() -> sqlite3.Connection:
     if _is_mysql():
         import pymysql
-        return pymysql.connect(
+        conn = pymysql.connect(
             host=_MYSQL_HOST,
             port=_MYSQL_PORT,
             user=_MYSQL_USER,
@@ -37,6 +77,7 @@ def _get_conn() -> sqlite3.Connection:
             cursorclass=pymysql.cursors.DictCursor,
             autocommit=False,
         )
+        return _PyMySQLCompatConn(conn)
     os.makedirs(os.path.dirname(_DB_PATH), exist_ok=True)
     conn = sqlite3.connect(_DB_PATH)
     conn.row_factory = sqlite3.Row