Starting migration: Add exchange column to crypto_market_autotrader_positions
==========================================================================

✓ Exchange column already exists

Positions with empty exchange: 0
✓ All positions already have exchange values

Checking index on exchange column...
✓ Index already exists

Exchange distribution in positions:
  - blofin: 643 positions
  - papertrade: 393 positions
  - kraken: 230 positions
  - apex: 4 positions

==========================================================================
Migration completed successfully!