fix: asyncpg param 한도 초과 — INSERT CHUNK 2900→2300

interval 컬럼 추가로 row당 파라미터 14개로 증가.
2900 × 14 = 40,600 > 32,767 → InterfaceError 발생.
2300 × 14 = 32,200으로 안전 범위 내 수정.

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

app/services/alpaca_price_service.py

@@ -164,8 +164,11 @@ class AlpacaPriceService:
                     })
 
             if rows:
-                # Chunk to stay under asyncpg's 32767-param limit (~11 params/row → 2900/chunk)
-                CHUNK = 2900
+                # Chunk to stay under asyncpg's 32767-param limit (14 params/row → 2300/chunk)
+                # 14 params: id/ticker/date/open/high/low/close/volume/vwap/trade_count/
+                #             interval/data_source/created_at/updated_at
+                # 2300 × 14 = 32,200 < 32,767
+                CHUNK = 2300
                 for i in range(0, len(rows), CHUNK):
                     stmt = pg_insert(AlpacaPriceData).values(rows[i : i + CHUNK])
                     stmt = stmt.on_conflict_do_nothing(constraint="uq_alpaca_price_data")