feat(travel-proxy): 신규 폴더 자동 탐색 + region_map 오버라이드 분리

- indexer: travel_root 전체 서브디렉토리 스캔하여 region_map에 없는 폴더도 자동 인덱싱
- RO 원본 대신 RW thumb_root에 region_map_extra.json으로 오버라이드 저장
- regions API: 미분류 지역 동적 추가
- sync 응답에 discovered 필드 추가

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

travel-proxy/app/indexer.py

@@ -64,6 +64,64 @@ def _generate_thumb(src: Path, dest: Path) -> bool:
         return False
 
 
+def _load_region_map_merged(region_map_path: Path, thumb_root: Path) -> dict:
+    """
+    원본 region_map.json + RW 오버라이드 파일 병합.
+    원본은 RO 마운트이므로 신규 폴더는 thumb_root/region_map_extra.json에 저장.
+    """
+    try:
+        with open(region_map_path, "r", encoding="utf-8") as f:
+            region_map = json.load(f)
+    except (FileNotFoundError, json.JSONDecodeError) as e:
+        logger.error("Failed to load region_map: %s", e)
+        raise
+
+    # 오버라이드 파일 병합
+    extra_path = thumb_root / "region_map_extra.json"
+    if extra_path.exists():
+        try:
+            with open(extra_path, "r", encoding="utf-8") as f:
+                extra = json.load(f)
+            for k, v in extra.items():
+                if k in region_map:
+                    # 기존 지역에 앨범 추가 (중복 방지)
+                    existing = region_map[k]
+                    if isinstance(existing, list) and isinstance(v, list):
+                        merged = list(dict.fromkeys(existing + v))
+                        region_map[k] = merged
+                else:
+                    region_map[k] = v
+        except (json.JSONDecodeError, OSError) as e:
+            logger.warning("Failed to load region_map_extra: %s", e)
+
+    return region_map
+
+
+def _save_extra_albums(thumb_root: Path, new_folders: List[str]) -> None:
+    """신규 발견 폴더를 RW 영역의 오버라이드 파일에 저장."""
+    extra_path = thumb_root / "region_map_extra.json"
+    extra = {}
+    if extra_path.exists():
+        try:
+            with open(extra_path, "r", encoding="utf-8") as f:
+                extra = json.load(f)
+        except (json.JSONDecodeError, OSError):
+            extra = {}
+
+    uncategorized = extra.get("미분류", [])
+    existing = set(uncategorized)
+    added = [f for f in new_folders if f not in existing]
+    if added:
+        uncategorized.extend(added)
+        extra["미분류"] = uncategorized
+        try:
+            with open(extra_path, "w", encoding="utf-8") as f:
+                json.dump(extra, f, ensure_ascii=False, indent=2)
+            logger.info("Saved %d new folders to region_map_extra.json → 미분류", len(added))
+        except OSError as e:
+            logger.warning("Cannot write region_map_extra: %s", e)
+
+
 def sync(
     travel_root: Path,
     thumb_root: Path,
@@ -73,17 +131,13 @@ def sync(
     폴더 스캔 → DB 동기화 + 썸네일 일괄 생성.
 
     Returns:
-        {"added": int, "removed": int, "thumbs_generated": int, "duration_sec": float}
+        {"added": int, "removed": int, "thumbs_generated": int,
+         "discovered": int, "duration_sec": float}
     """
     start = time.time()
 
-    # 1. region_map.json에서 전체 앨범 폴더 수집
-    try:
-        with open(region_map_path, "r", encoding="utf-8") as f:
-            region_map = json.load(f)
-    except (FileNotFoundError, json.JSONDecodeError) as e:
-        logger.error("Failed to load region_map: %s", e)
-        raise
+    # 1. region_map.json + 오버라이드 병합
+    region_map = _load_region_map_merged(region_map_path, thumb_root)
 
     all_albums: Set[str] = set()
     for v in region_map.values():
@@ -92,6 +146,35 @@ def sync(
         elif isinstance(v, dict) and isinstance(v.get("albums"), list):
             all_albums.update(v["albums"])
 
+    # 1-b. 파일시스템에서 신규 폴더 자동 탐색
+    discovered = 0
+    new_folders = []
+    try:
+        with os.scandir(travel_root) as entries:
+            for entry in entries:
+                if not entry.is_dir() or entry.name.startswith("_"):
+                    continue
+                if entry.name in all_albums:
+                    continue
+                # 이미지가 하나라도 있는 폴더만 추가
+                folder = travel_root / entry.name
+                has_images = any(
+                    Path(f.name).suffix.lower() in IMAGE_EXT
+                    for f in os.scandir(folder)
+                    if f.is_file()
+                )
+                if has_images:
+                    all_albums.add(entry.name)
+                    new_folders.append(entry.name)
+                    discovered += 1
+                    logger.info("Discovered new album folder: %s", entry.name)
+    except OSError as e:
+        logger.warning("Failed to scan travel_root for new folders: %s", e)
+
+    # 신규 폴더를 RW 오버라이드 파일에 영구 저장
+    if new_folders:
+        _save_extra_albums(thumb_root, new_folders)
+
     # 2. 각 앨범 폴더 스캔 → DB 배치 동기화
     added = 0
     updated = 0
@@ -123,8 +206,8 @@ def sync(
 
     duration = round(time.time() - start, 2)
     logger.info(
-        "Sync complete: added=%d updated=%d removed=%d thumbs=%d duration=%.2fs",
-        added, updated, removed, thumbs_generated, duration,
+        "Sync complete: added=%d updated=%d removed=%d thumbs=%d discovered=%d duration=%.2fs",
+        added, updated, removed, thumbs_generated, discovered, duration,
     )
 
     return {
@@ -132,5 +215,6 @@ def sync(
         "updated": updated,
         "removed": removed,
         "thumbs_generated": thumbs_generated,
+        "discovered": discovered,
         "duration_sec": duration,
     }