This task implements a "Stop Stream" capability for the DevIndex application to allow users to cancel large data streams. This is a critical usability feature for users on slow or metered connections.

Objectives:

1. Proxy Enhancement (src/data/proxy/Stream.mjs):
   • Implement an abort() method using AbortController.
   • Ensure the fetch request and stream reader are properly cancelled.
   • Gracefully handle the abort signal without throwing visible errors to the user (unless intended).
2. Store Integration (src/data/Store.mjs):
   • Expose an abort() method that delegates to the active proxy.
   • Ensure the store state (isLoading, isStreaming) is correctly reset upon cancellation.
3. UI Implementation (apps/devindex/view/home/StatusToolbar.mjs):
   • Add a "Stop" button (icon: fa-stop or fa-ban) next to the progress bar.
   • Bind the button's visibility to the store's loading state.
   • Wire the click event to the store's abort() method.

Acceptance Criteria:

• Stream.abort() successfully cancels the network request.
• Store.abort() stops the loading process and resets loading flags.
• The grid remains functional with the data loaded up to the point of cancellation.
• A "Stop" button appears in the StatusToolbar during streaming and disappears when finished or stopped.
• Clicking the "Stop" button cancels the stream immediately.