BOLT-917 Phase 2: RawApiCall retention/cleanup strategy

Phase 1 (PR #10564) writes a RawApiCall row per Smartcar command. At ~15-min cadence × N vehicles this table grows fast with no TTL. For Phase 2 decide: (a) partition by createdAt (monthly), (b) cron-driven DELETE older than N days, or (c) S3 cold-archive tier. Tie cleanup window to debug needs (probably 14-30d hot in pg, longer cold). Also evaluate batching writes to reduce GC pressure from toJsonSafe round-trip on large response bodies if polling/webhook flows start archiving.