perf(travel-proxy): 배치 DB 연결 + nginx sync timeout 600s

- db.py: batch_sync_album, batch_mark_thumbs_done 추가
- indexer.py: 앨범 단위 배치 동기화로 전환
- nginx: /api/travel/ proxy_read_timeout 600s 추가

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

travel-proxy/app/db.py

@@ -175,3 +175,59 @@ def mark_thumb_done(album: str, filename: str) -> None:
             "UPDATE photos SET has_thumb = 1 WHERE album = ? AND filename = ?",
             (album, filename),
         )
+
+
+def batch_sync_album(album: str, items: List[Dict[str, Any]], existing_filenames: Set[str]) -> Dict[str, int]:
+    """앨범 단위 배치 동기화. 단일 커넥션으로 upsert + 삭제 처리."""
+    added = updated = 0
+    with _conn() as conn:
+        for item in items:
+            existing = conn.execute(
+                "SELECT mtime FROM photos WHERE album = ? AND filename = ?",
+                (album, item["filename"]),
+            ).fetchone()
+            if not existing:
+                conn.execute(
+                    "INSERT INTO photos (album, filename, mtime, has_thumb) VALUES (?, ?, ?, 0)",
+                    (album, item["filename"], item["mtime"]),
+                )
+                added += 1
+            elif existing["mtime"] != item["mtime"]:
+                conn.execute(
+                    "UPDATE photos SET mtime = ?, has_thumb = 0 WHERE album = ? AND filename = ?",
+                    (item["mtime"], album, item["filename"]),
+                )
+                updated += 1
+
+        # 삭제 처리
+        db_rows = conn.execute(
+            "SELECT filename FROM photos WHERE album = ?", (album,)
+        ).fetchall()
+        db_filenames = {r["filename"] for r in db_rows}
+        to_remove = db_filenames - existing_filenames
+
+        removed = len(to_remove)
+        if to_remove:
+            placeholders = ",".join("?" for _ in to_remove)
+            conn.execute(
+                f"DELETE FROM photos WHERE album = ? AND filename IN ({placeholders})",
+                [album, *to_remove],
+            )
+            conn.execute(
+                f"DELETE FROM album_covers WHERE album = ? AND filename IN ({placeholders})",
+                [album, *to_remove],
+            )
+
+    return {"added": added, "updated": updated, "removed": removed}
+
+
+def batch_mark_thumbs_done(items: List[Dict[str, str]]) -> None:
+    """썸네일 생성 완료 배치 표시."""
+    if not items:
+        return
+    with _conn() as conn:
+        for item in items:
+            conn.execute(
+                "UPDATE photos SET has_thumb = 1 WHERE album = ? AND filename = ?",
+                (item["album"], item["filename"]),
+            )