Perf: Optimize multi-pool health check with batched storage reads

[devdianax]

Context

Liquidators and frontends query health across multiple pools. Each query is a separate storage read.

Current Limitation/Problem

Health check per pool requires separate cross-contract call. N pools = N calls with N storage reads each.

Expected Outcome

Batched health check function that reads multiple pool states in a single call and computes health for all.

Acceptance Criteria

• BatchView function: accepts array of (pool, user, asset) tuples
• Single storage read to load pool config for all queried pools
• Parallel health computation: no cross-contract calls between computations
• Response: array of health factors, collateral values, debt values
• Gas comparison: batched vs individual per query count
• Pagination for large queries (100+ positions)
• Caching: cache batched results within transaction scope

Technical Scope

• contracts/lending-pool/src/batch_view.rs - batched health check
• Frontend use: batch all visible positions in single query
• Gas benchmark: individual vs batched at various query sizes
• Edge cases: partial results on pool failure, stale data in cached results