fix: Show all tags in LoRA Pool without limit (#819)

- Backend: Support limit=0 to return all tags in top-tags API
- Frontend: Remove tags limit setting and fetch all tags by default
- UI: Implement virtual scrolling in TagsModal for performance
  - Initial display 200 tags, load more on scroll
  - Show all results when searching
- Remove lora_pool_tags_limit setting to simplify UX

Fixes #819

py/routes/handlers/model_handlers.py

@@ -648,7 +648,7 @@ class ModelQueryHandler:
     async def get_top_tags(self, request: web.Request) -> web.Response:
         try:
             limit = int(request.query.get("limit", "20"))
-            if limit < 1 or limit > 100:
+            if limit < 0:
                 limit = 20
             top_tags = await self._service.get_top_tags(limit)
             return web.json_response({"success": True, "tags": top_tags})