Add multi-tag filtering with active tag display, optimize directory browsing performance, and improve mobile editor UI

backend/main.py

@@ -114,13 +114,16 @@ async def api_browse(vault_name: str, path: str = ""):
                 continue
             rel = str(entry.relative_to(vault_root)).replace("\\", "/")
             if entry.is_dir():
-                # Count all supported files recursively (skip hidden dirs)
-                file_count = sum(
-                    1 for f in entry.rglob("*")
-                    if f.is_file()
-                    and not any(p.startswith(".") for p in f.relative_to(entry).parts)
-                    and (f.suffix.lower() in SUPPORTED_EXTENSIONS or f.name.lower() in ("dockerfile", "makefile"))
-                )
+                # Count only direct children (files and subdirs) for performance
+                try:
+                    file_count = sum(
+                        1 for child in entry.iterdir()
+                        if not child.name.startswith(".")
+                        and (child.is_file() and (child.suffix.lower() in SUPPORTED_EXTENSIONS or child.name.lower() in ("dockerfile", "makefile"))
+                             or child.is_dir())
+                    )
+                except PermissionError:
+                    file_count = 0
                 items.append({
                     "name": entry.name,
                     "path": rel,