Tabbed UI, browse caching, and bottom mini player

- Convert stacked sections to tabbed interface (Player, Browser, Actions, Scripts, Callbacks) with localStorage persistence
- Add in-memory directory listing cache (5-min TTL) with nocache bypass for refresh
- Defer stat()/duration calls to paginated items only for faster browse
- Move mini player from top to bottom with footer padding fix
- Always show scrollbar to prevent layout shift between tabs
- Add tab localization keys (en/ru)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

media_server/routes/browser.py

@@ -218,6 +218,7 @@ async def browse(
     path: str = Query(default="", description="Path relative to folder root"),
     offset: int = Query(default=0, ge=0, description="Pagination offset"),
     limit: int = Query(default=100, ge=1, le=1000, description="Pagination limit"),
+    nocache: bool = Query(default=False, description="Bypass directory cache"),
     _: str = Depends(verify_token),
 ):
     """Browse a directory and list files/folders.
@@ -244,6 +245,7 @@ async def browse(
             path=decoded_path,
             offset=offset,
             limit=limit,
+            nocache=nocache,
         )
 
         return result