fix(travel-proxy): db.py 중복 쿼리 제거 + 타입 힌트 개선

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

travel-proxy/app/db.py

@@ -1,6 +1,6 @@
 import os
 import sqlite3
-from typing import Any, Dict, List, Optional
+from typing import Any, Dict, List, Optional, Set
 
 DB_PATH = os.getenv("TRAVEL_DB_PATH", "/data/thumbs/travel.db")
 
@@ -50,12 +50,7 @@ def get_photos_by_region(albums: List[str], page: int, size: int) -> Dict[str, A
             albums,
         ).fetchall()
         matched_albums = [{"album": r["album"], "count": r["cnt"]} for r in rows]
-
-        total_row = conn.execute(
-            f"SELECT COUNT(*) as cnt FROM photos WHERE album IN ({placeholders})",
-            albums,
-        ).fetchone()
-        total = total_row["cnt"]
+        total = sum(r["cnt"] for r in rows)
 
         offset = (page - 1) * size
         items = conn.execute(
@@ -142,7 +137,7 @@ def upsert_photo(album: str, filename: str, mtime: float) -> str:
         return "unchanged"
 
 
-def remove_missing_photos(album: str, existing_filenames: set) -> int:
+def remove_missing_photos(album: str, existing_filenames: Set[str]) -> int:
     """폴더에 없는 사진을 DB에서 제거. 제거 수 반환."""
     with _conn() as conn:
         db_rows = conn.execute(