fix: updater crashes on os.makedirs PermissionError + prune protected dirs

os.makedirs was outside try/except so permission-denied on .github
directory creation crashed the entire update. Now both makedirs and
copy are caught. Also prunes protected dirs from os.walk so the
updater never even enters .github, .git, .claude, etc.

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

Former-commit-id: d4bdef4604095a82860a4bc91bec3435a878f899

backend/services/updater.py

@@ -159,7 +159,10 @@ def _extract_and_copy(zip_path: str, project_root: str, temp_dir: str) -> int:
     copied = 0
     skipped = 0
 
-    for root, _dirs, files in os.walk(base):
+    for root, dirs, files in os.walk(base):
+        # Prune protected directories so os.walk never descends into them
+        dirs[:] = [d for d in dirs if d not in _PROTECTED_DIRS]
+
         for fname in files:
             src = os.path.join(root, fname)
             rel = os.path.relpath(src, base).replace("\\", "/")
@@ -169,8 +172,8 @@ def _extract_and_copy(zip_path: str, project_root: str, temp_dir: str) -> int:
                 continue
 
             dst = os.path.join(project_root, rel)
-            os.makedirs(os.path.dirname(dst), exist_ok=True)
             try:
+                os.makedirs(os.path.dirname(dst), exist_ok=True)
                 shutil.copy2(src, dst)
                 copied += 1
             except (PermissionError, OSError) as e: