Large JSON serialization blocks event loop for 100ms+

Serializing large payloads (100k+ records, 5MB+) with JSON.stringify blocks the event loop for 100-150ms, queuing all other requests. Example: 100k records = 142ms stringify, 98ms parse.

Implement pagination with max 200 records per response. Use fast-json-stringify with predefined schemas for 2-5x speedup. For exports, stream JSON response in batches instead of building full array in memory.