Fix Booking.com scrape saves — widen room_type to TEXT + rollback per failure

Scraped room descriptions exceed VARCHAR(100) (StringDataRightTruncation),
and the failed insert poisoned the transaction so every subsequent save in
the batch died with InFailedSqlTransaction — scrapes reported success with
0 rows saved. Widen the column (with ALTER for existing tables) and roll
back after a failed save.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

backend/services/booking_scraper.py

@@ -349,6 +349,9 @@ async def scrape_date(
             rates_saved += 1
         except Exception as e:
             logger.warning(f"Error saving hotel/rate: {e}")
+            # A failed statement aborts the transaction — roll back so the
+            # remaining hotels in this batch can still be saved
+            db.rollback()
             continue
 
     db.commit()