Refactor Neo.data.Store and Neo.data.proxy.Stream to optimize progressive loading and prevent UI blocking.

Key Changes:

1. Eliminate Duplicate Load Events: Remove manual load event firing in Store.onData. Rely on onCollectionMutate to trigger load events naturally when data is added, preventing double-firing for every chunk.
2. Unblock UI during Streaming: Introduce await me.timeout(5) in the Stream proxy's read loop. This yields control to the App Worker's event loop, allowing it to process VDOM updates and other events while parsing a large stream.
3. Track Streaming State: Introduce isStreaming flag on the Store (managed via the Proxy) to distinguish between intermediate progressive updates and the final load completion.
4. Base Proxy Enhancement: Add store config to Neo.data.proxy.Base to give proxies direct access to their owner store.

Goal: Ensure smooth, progressive rendering for large datasets (e.g., DevIndex) without freezing the UI.