feat: personalize and stream mentor chat

database.py

@@ -257,6 +257,19 @@ class ReviewDatabase:
                 CREATE INDEX IF NOT EXISTS idx_mentor_messages_conversation
                 ON mentor_messages(user_id, mentor_id, trade_date, id DESC);
 
+                CREATE TABLE IF NOT EXISTS mentor_preferences (
+                    user_id INTEGER NOT NULL,
+                    mentor_id TEXT NOT NULL,
+                    pinned INTEGER NOT NULL DEFAULT 0,
+                    sort_order INTEGER NOT NULL DEFAULT 0,
+                    updated_at TEXT NOT NULL,
+                    PRIMARY KEY (user_id, mentor_id),
+                    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+                );
+
+                CREATE INDEX IF NOT EXISTS idx_mentor_preferences_user_order
+                ON mentor_preferences(user_id, pinned DESC, sort_order, mentor_id);
+
                 CREATE TABLE IF NOT EXISTS strategy_tracks (
                     id INTEGER PRIMARY KEY AUTOINCREMENT,
                     user_id INTEGER NOT NULL,
@@ -1417,6 +1430,48 @@ class ReviewDatabase:
             )
             return int(cursor.rowcount)
 
+    def list_mentor_preferences(self, user_id: int) -> list[dict[str, Any]]:
+        with self.connect() as connection:
+            rows = connection.execute(
+                """
+                SELECT mentor_id, pinned, sort_order
+                FROM mentor_preferences
+                WHERE user_id = ?
+                ORDER BY sort_order, mentor_id
+                """,
+                (int(user_id),),
+            ).fetchall()
+        return [
+            {
+                "mentor_id": str(row["mentor_id"]),
+                "pinned": bool(row["pinned"]),
+                "sort_order": int(row["sort_order"]),
+            }
+            for row in rows
+        ]
+
+    def save_mentor_preferences(
+        self, user_id: int, ordered_ids: list[str], pinned_ids: set[str]
+    ) -> None:
+        now = datetime.now().astimezone().isoformat(timespec="seconds")
+        values = [
+            (int(user_id), mentor_id, int(mentor_id in pinned_ids), index, now)
+            for index, mentor_id in enumerate(ordered_ids)
+        ]
+        with self.connect() as connection:
+            connection.execute(
+                "DELETE FROM mentor_preferences WHERE user_id = ?",
+                (int(user_id),),
+            )
+            connection.executemany(
+                """
+                INSERT INTO mentor_preferences
+                    (user_id, mentor_id, pinned, sort_order, updated_at)
+                VALUES (?, ?, ?, ?, ?)
+                """,
+                values,
+            )
+
     def save_strategy_tracks(
         self,
         user_id: int,