Frontend Redesign and Curation Pipeline Parity

[google-labs-jules]

The project has been significantly improved to bring the web application to parity with the CLI curation tool.

Key changes include:

1. Backend Enhancements: Added endpoints for curation initialization and results management. Updated the SSE stream to pass structured data for tournament results, core constraints, and search statistics. Every search now saves its full state to a JSON file in the results/ folder.
2. Frontend Redesign: A complete UI overhaul using a modern, dark theme with visual feedback for every stage of the AI curation pipeline. Users can now see mandatory constraints and query variations before launching a search.
3. Tournament Visualization: Added a live-updating tournament view that shows the performance of 5 different query variations in real-time, highlighting the winner.
4. Dynamic Results: The app now loads search results (both live and from history) dynamically from JSON, allowing for interactive features like keyword highlighting, content expansion, and favoriting.
5. History System: A side-panel history browser was added to navigate and reload past curation results instantly.

These changes fulfill all requirements in @FRONTEND_REQUIREMENTS.md and address the inconsistencies between the CLI and web versions.

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PR created automatically by Jules for task 5956653998854967433 started by @Esashiero

[google-labs-jules]

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