feat: integrate Pong game scoreboard with silent updates and layout refinements

[sugoi-yuzuru]

Description

Overview

This pull request introduces a dedicated, dynamic A2UI scoreboard component for the embedded Pong application and refactors the overall interface into a seamless side-by-side layout. Additionally, it implements a "silent" message flag to ensure frequent score updates no longer generate visible chat bubbles, significantly reducing UI clutter.

Key Changes

• A2UI Components: Introduced PongLayout and PongScoreBoard Angular components and registered them in the catalog (catalog.ts, pong-layout.ts, pong-scoreboard.ts).
• Silent Tool Calls: Added a silent boolean flag to the chat service error handling and updated the core tool definitions to mute chat bubbles during continuous score synchronization (chat-service.ts, tools.py).
• Agent Catalogs: Updated the v0.8 and v0.9 mcp_app_catalog.json manifests to support the newly registered Pong UI elements (mcp_app_catalog.json, agent.py).
• App Layout & Logic: Refactored the core pong_app.html iframe layout to separate the game canvas and the scoreboard correctly using CSS Flexbox. Also cleaned up internal pause and state management logic.

Verification

• Verified that the Pong game and styling render correctly side-by-side without overlapping or vertical cutoff.
• Confirmed that real-time score updates are synchronized successfully with the agent without polluting the chat feed.
• Evaluated internal game mechanics (like unpausing and state synchronization) to ensure they work smoothly amidst the new UI structure.

Screencast video: https://screencast.googleplex.com/cast/NTExMjc5MjI0MjcxNjY3Mnw2ODBkNzkzYy1mMg

Pre-launch Checklist

• I signed the CLA.
• I read the Contributors Guide.
• I read the Style Guide.
• I have added updates to the CHANGELOG.
• I updated/added relevant documentation.
• My code changes (if any) have tests.

If you need help, consider asking for advice on the discussion board.

[gemini-code-assist]

Code Review

This pull request refactors the Pong game to use a native scoreboard by introducing a new PongLayout and PongScoreBoard component. It moves the game's score state to the server-side, utilizing a new score_update tool and implementing 'silent' message support in the chat service to handle background updates. Feedback focuses on critical security vulnerabilities regarding postMessage origin validation, potential race conditions in the Python backend due to global state, and a JavaScript hoisting issue in the HTML. Additionally, there are recommendations to improve maintainability by extracting inline scripts and styles into dedicated files.