⚡ Bolt: Fix N+1 query problem in PoolController

[zaydiscold]

💡 What: Added getLocalKeysForAccounts to batch-fetch keys for multiple accounts in a single query, replacing the per-account getLocalKeys query in PoolController's main account mapping loop.
🎯 Why: The existing PoolController.getPoolData loop hit the database independently to get local keys for every single account loaded. This caused an N+1 query problem resulting in high latency when a user has many accounts in their Hydra instance.
📊 Impact: Reduces database queries in /api/pool from O(N) to O(1) where N is the number of accounts. Substantially decreases server load and speeds up the Pool Manager loading time on large account lists.
🔬 Measurement: Verify by testing the /api/pool endpoint with a large number of accounts. The database query logs will show 1 fetch rather than N.

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PR created automatically by Jules for task 3205942739633734401 started by @zaydiscold

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