⚡ Bolt: Fix N+1 query in PoolController.getPoolData by batching local keys fetch

[zaydiscold]

💡 What: The optimization implements a single batched database query store.getAllLocalKeys to fetch all local key records for a user at once, replacing the N individual database queries previously executed inside the Promise.allSettled loop in PoolController.getPoolData. The retrieved keys are indexed into an in-memory Map for O(1) lookups during iteration.

🎯 Why: The previous implementation suffered from an N+1 query problem, hitting the database once for each account. As the number of accounts grows, this pattern causes high database load and latency.

📊 Impact: Reduces the number of database queries in the getPoolData endpoint from N+1 (one for accounts, plus one for every account's keys) to exactly 2, regardless of how many accounts the user has.

🔬 Measurement: Verify the improvement by running a trace on database queries during a request to /api/pool. The number of SELECT * FROM Key queries will now be 1, rather than scaling linearly with the number of accounts.

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PR created automatically by Jules for task 16955008338495311246 started by @zaydiscold

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