fix: timeseries.json not regenerated since Apr 29 + ci_pass_rate_pct stale

[zacharias-ona]

Two issues spotted from the software-factory.dev sync:

1. metrics/timeseries.json stopped updating after Apr 29

The build-timeseries.mjs aggregator was added in #863 and is supposed to run as the final step of the daily-metrics cron. Daily snapshots for Apr 30 and May 1 were committed normally, but timeseries.json was not regenerated — it still shows updatedAt: 2026-04-29T21:55:19Z with 16 days ending at Apr 29.

Likely cause: the aggregator step is either erroring silently or not being invoked by the daily automation.

2. Top-level ci_pass_rate_pct is null while ci.pass_rate_pct has data

In the May 1 daily snapshot:

{
  "ci_pass_rate_pct": null,
  "ci": {
    "runs_total": 6,
    "runs_passed": 6,
    "pass_rate_pct": 100.0
  }
}

The top-level ci_pass_rate_pct field appears to no longer be populated. The software-factory.dev sync was reading this field, which caused the landing page to show null%. We've switched our sync to read ci.pass_rate_pct instead, but the top-level field should either be kept in sync or formally deprecated.

Impact

• Dashboard charts on software-factory.dev were stuck at Apr 29. We've added a fallback in our sync automation to patch missing days from daily snapshots, but the proper fix is for the aggregator to run.
• The null CI value was visible on the live landing page until we added null guards.