fix: all users get subfolders, nobody owns the mount root

Every user — including the initial admin — now gets their own
subdirectory under PHOTO_DIRS (e.g. /photos/admin, /photos/bob).
No one's source root points to the mount root itself, eliminating
cross-user photo overlap entirely.

- Setup endpoint: admin gets /photos/{username} like everyone else
- Migration: default admin media_path set to /photos/admin
- Remove scan directory pruning (no longer needed)
- Fix thumbnail retry URL: use & separator when token query param
  already present (was producing ?token=...?retry=N)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/alembic/versions/0009_users_and_auth.py

@@ -80,7 +80,7 @@ def upgrade() -> None:
         pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
         hashed = pwd_context.hash(generated_password)
 
-        # The default admin's media_path is the legacy /photos root
+        # Every user gets a subfolder — including the migrated admin.
         conn.execute(
             sa.text(
                 "INSERT INTO users (id, username, hashed_password, role, media_path) "
@@ -91,7 +91,7 @@ def upgrade() -> None:
                 "username": "admin",
                 "hashed": hashed,
                 "role": "admin",
-                "media_path": "/photos",
+                "media_path": "/photos/admin",
             },
         )
 

backend/app/routers/auth.py

@@ -161,9 +161,9 @@ async def setup(body: SetupRequest, db: AsyncSession = Depends(get_db)):
     if len(body.password) < 6:
         raise HTTPException(status_code=400, detail="Password must be at least 6 characters")
 
-    # The initial admin owns the entire photo mount root. Regular users
-    # (created later via admin panel) get a subdirectory under it.
-    media_path = settings.photo_dirs
+    # Every user — including the initial admin — gets their own subfolder
+    # under the photo mount root. Nobody owns the root directory itself.
+    media_path = os.path.join(settings.photo_dirs, body.username.strip())
     os.makedirs(media_path, exist_ok=True)
 
     user = User(

backend/app/tasks/scan.py

@@ -164,28 +164,11 @@ async def _scan_folder_async(folder_path: str, source_root_id: Optional[str], ta
                 hidden_folder_cache[folder_row.id] = False
                 return False
 
-            # Build a set of paths owned by OTHER users' source roots so
-            # the admin's scan of /photos doesn't descend into /photos/bob.
-            other_root_paths: set[str] = set()
-            if owner_user_id:
-                other_roots = (await session.execute(
-                    select(SourceRoot.path)
-                    .where(SourceRoot.is_active == True)  # noqa: E712
-                    .where(SourceRoot.user_id != owner_user_id)
-                )).scalars().all()
-                other_root_paths = {os.path.normpath(p) for p in other_roots}
-
-            def _should_skip_dir(dirpath: str) -> bool:
-                """True if dirpath is another user's source root."""
-                return os.path.normpath(dirpath) in other_root_paths
-
             # Pre-walk to compute the total file count upfront. Without this
             # the progress bar would jump every time a new subfolder is
             # encountered because the running total kept growing.
             total_files = 0
             for _root, _dirs, files in os.walk(folder_path):
-                # Prune other users' directories from count
-                _dirs[:] = [d for d in _dirs if not _should_skip_dir(os.path.join(_root, d))]
                 total_files += sum(
                     1 for f in files if Path(f).suffix.lower() in SUPPORTED_EXTENSIONS
                 )
@@ -196,9 +179,6 @@ async def _scan_folder_async(folder_path: str, source_root_id: Optional[str], ta
             errors = []
 
             for root, dirs, files in os.walk(folder_path):
-                # Skip directories that belong to other users' source roots
-                dirs[:] = [d for d in dirs if not _should_skip_dir(os.path.join(root, d))]
-
                 # Get or create folder entry
                 folder = await get_or_create_folder(session, root, source_root_id, owner_user_id)
                 progress_set(REDIS_KEY_CURRENT_FOLDER, root)

frontend/src/components/timeline/PhotoThumbnail.tsx

@@ -100,7 +100,8 @@ export function PhotoThumbnail({
   // Cache-bust on retry so the browser actually re-requests instead of
   // serving the cached 404.
   const baseUrl = photosApi.getThumbnailUrl(photo.id, 'medium')
-  const thumbnailUrl = retryCount > 0 ? `${baseUrl}?retry=${retryCount}` : baseUrl
+  const sep = baseUrl.includes('?') ? '&' : '?'
+  const thumbnailUrl = retryCount > 0 ? `${baseUrl}${sep}retry=${retryCount}` : baseUrl
 
   // "Capture date probably wrong" — read straight from the stored
   // `has_date_warning` flag rather than recomputing the heuristic