Cache stats:
- hit_rate is now token-level (cache_read / total_input) not request-level
- Track uncached_input_tokens per provider in metrics
- Preserve request_hit_rate as secondary metric
Compression-vs-cache:
- Detect when compression busts the prefix cache (expected_cached - actual_read)
- Two simple session-level numbers: tokens_saved vs cache_bust_tokens
- Log CACHE-BUST per request, aggregate in /stats and telemetry beacon
- Single new column in proxy_telemetry_v2: cache_bust_tokens
Dashboard infra:
- SQL for dashboard_summary table + pg_cron hourly refresh
- Hourly + daily aggregation from proxy_telemetry_v2
- Upgrade scripts for adding hourly_stats and cache bust columns
