Enhance HistoryTable Component with Infinite Scroll and Cache Management

- Updated HistoryTable to implement infinite scrolling for loading history items dynamically.
- Introduced state management for accumulated history and total item count.
- Added Intersection Observer for triggering additional data fetches when scrolling.
- Implemented cache clearing functionality in the backend to manage voice prompt caches effectively.
- Improved loading indicators and user feedback for data fetching states.
- Refactored code for better readability and maintainability.

backend/backends/pytorch_backend.py

@@ -196,6 +196,8 @@ class PyTorchTTSBackend:
                 # Cache stores as torch.Tensor but actual prompt is dict
                 # Convert if needed
                 if isinstance(cached_prompt, dict):
+                    # For PyTorch backend, the dict should contain tensors, not file paths
+                    # So we can safely return it
                     return cached_prompt, True
                 elif isinstance(cached_prompt, torch.Tensor):
                     # Legacy cache format - convert to dict