library: hidden segments are never assets

The everything-indexes sweep pulled .thumbs/ cache files in as rows; fixing
one sent a thumb path into the dispatcher (unknown asset). One rule, both
writers: any path segment starting with a dot is excluded — forks and cache
trees alike.

middleware/studio_home.py

@@ -143,11 +143,11 @@ def _save_library(root: Path, lib: dict) -> None:
 
 
 def _safe_asset(root: Path, rel: str) -> Path | None:
-    p = (root / rel).resolve()
-    if p.name.startswith("."):
-        # Dotfiles are never assets (AppleDouble forks carry image extensions
-        # but serve resource-fork bytes) — refuse them everywhere at once.
+    if any(part.startswith(".") for part in Path(rel).parts):
+        # Hidden segments are never assets — AppleDouble forks AND cache
+        # trees (.thumbs/) in one rule, refused everywhere at once.
         return None
+    p = (root / rel).resolve()
     return p if p.is_file() and str(p).startswith(str(root.resolve())) else None
 
 

scripts/library_manifest.py

@@ -91,12 +91,13 @@ def classify(relpath: str, slugs: set[str]) -> dict | None:
 def scan(root: str) -> list[str]:
     """All manifestable image paths (relative to root), sorted for stable diffs."""
     found: list[str] = []
-    for base, _dirs, files in os.walk(root):
+    for base, dirs, files in os.walk(root):
+        # Hidden segments are never assets — one rule covering AppleDouble
+        # forks (._foo.png) AND cache trees (.thumbs/ thumbnails indexed as
+        # library rows sent thumb paths into the fix dispatcher).
+        dirs[:] = [d for d in dirs if not d.startswith(".")]
         for f in files:
             if f.startswith("."):
-                # Dotfiles are never assets: `._foo.png` AppleDouble forks ride
-                # along with mac transfers, carry an image extension, and are
-                # resource-fork bytes that render 0x0 in the library.
                 continue
             ext = os.path.splitext(f)[1].lower()
             full = os.path.join(base, f)