Add migration for race_id column on existing passages table

CREATE TABLE IF NOT EXISTS does not add new columns to existing tables.
Use ALTER TABLE to migrate databases that predate this change.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/profile_db.py

@@ -51,17 +51,30 @@ async def init_db(db: aiosqlite.Connection) -> None:
         );
 
         CREATE INDEX IF NOT EXISTS idx_passages_profile ON passages(profile_id);
-        CREATE INDEX IF NOT EXISTS idx_passages_race ON passages(race_id);
         CREATE INDEX IF NOT EXISTS idx_passages_station ON passages(station);
         CREATE INDEX IF NOT EXISTS idx_passages_needs_review ON passages(needs_review);
         CREATE INDEX IF NOT EXISTS idx_passage_images_passage ON passage_images(passage_id);
     """)
     await db.commit()
 
+    # Migrer eksisterende tabeller
+    await _migrate(db)
+
     from race_db import init_race_tables
     await init_race_tables(db)
 
 
+async def _migrate(db: aiosqlite.Connection) -> None:
+    """Legg til nye kolonner i eksisterende tabeller ved oppgradering."""
+    async with db.execute("PRAGMA table_info(passages)") as cur:
+        columns = {row[1] for row in await cur.fetchall()}
+
+    if "race_id" not in columns:
+        await db.execute("ALTER TABLE passages ADD COLUMN race_id TEXT REFERENCES races(race_id)")
+        await db.execute("CREATE INDEX IF NOT EXISTS idx_passages_race ON passages(race_id)")
+        await db.commit()
+
+
 async def get_db() -> aiosqlite.Connection:
     db = await aiosqlite.connect(DB_PATH)
     db.row_factory = aiosqlite.Row