⚡ Bolt: batch pool controller local keys fetch

[zaydiscold]

💡 What: Implemented getAllLocalKeys to batch fetch local keys instead of issuing a separate query for each account inside PoolController.getPoolData's map loop. Grouped results in a map for O(1) loop resolution.

🎯 Why: Resolves an N+1 database query problem on the high-frequency /api/pool endpoint which scales linearly and reduces database connection saturation as users add more accounts.

📊 Impact: Reduces the number of database queries executed per pool data refresh from O(N+1) to O(2), significantly reducing database load, latency and Node event loop stalls for users with large account pools.

🔬 Measurement: Verifiable by monitoring database load during repeated polling to /api/pool and noting the reduction in individual findMany queries for local keys.

Tested successfully utilizing npm test, npm run lint, and npm run gate. The test:ensure-session-backfill test throws an expected environmental error linked to node:test mocking on Node 22 as logged in the existing memory, while remaining integration scripts pass cleanly. Recorded the learning about parallel N+1 queries in .jules/bolt.md.

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PR created automatically by Jules for task 7955037962684721079 started by @zaydiscold

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