Aggregates the existing execution_logs table (no hot-path instrumentation):
ExecutionLogRepository::summarize_for_app returns counts, error rate, latency
avg/p50/p95 (percentile_cont), by-status/by-source breakdowns, and an hourly
series over a trailing window (clamped 1h..90d). New metrics_api router at
GET /api/v1/admin/apps/{id}/metrics?window= (AppLogRead), and a dashboard
Metrics tab (summary cards + an inline-SVG per-hour bar chart, no JS dep).
Pinned by a manager-core test asserting the exact rollup (percentiles included)
and the empty-app zero case.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
