⚡ Bolt: cache blog api response globally to prevent redundant requests

[schmug]

💡 What: Added module-level fetchPromise and cachedPayload variables to BlogApp.tsx to handle fetching /api/blog.json, deduplicating requests across re-mounts.
🎯 Why: Previously, BlogApp ran a fetch directly inside useEffect on every mount. In a windowed OS-like environment where windows are frequently closed and opened, this results in significant redundant network requests and unnecessary intermediate loading states for data that is mostly static.
📊 Impact: Reduces redundant network requests for blog data by ~100% after the first open. Improves perceived load time to near-instant (0ms) on subsequent opens.
🔬 Measurement: Verified by ensuring zero type errors, tests passing, and running e2e test successfully. Verified there are no React memory leaks due to unmounted state updates via the cancelled boolean checking.

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PR created automatically by Jules for task 8655861366902805783 started by @schmug

[google-labs-jules]

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[schmug]

Superseded by #127 (merged to main), which consolidated the best of the duplicate Bolt/Sentinel/Palette scheduled-agent PRs into one reviewed change. Closing as duplicate.

[google-labs-jules]

Superseded by #127 (merged to main), which consolidated the best of the duplicate Bolt/Sentinel/Palette scheduled-agent PRs into one reviewed change. Closing as duplicate.

Understood. Acknowledging that this work is now obsolete as it has been superseded by #127. Stopping work on this task.