Implement scheduled metrics and reporting workflow

[ashleyshaw]

Summary

Metrics are collected ad-hoc in various workflows but not surfaced to the team on a regular schedule. There's no weekly summary or trending analysis.

Problem

• Metrics collected but not reported
• No visibility into workflow health trends
• Team unaware of SLA breaches, coverage gaps, or performance issues
• Metrics not aggregated for stakeholder reporting

Solution

Create new weekly-metrics-summary.yml workflow that:

1. Triggers on schedule: weekly (Monday 09:00 UTC)
2. Aggregates metrics from .github/metrics/:
   • Workflow run counts & durations
   • Linting trends (errors, warnings)
   • Test coverage (if available)
   • SLA metrics (aging, breach counts)
3. Generate summary markdown report
4. Post to:
   • GitHub discussion (metrics channel)
   • Wiki (historical trends)
   • Optional: Slack notification with key metrics
5. Archive weekly reports in .github/metrics/weekly/

Implementation Details

• Effort: 2 hours
• Complexity: Low
• Risk: Low (read-only, non-blocking)
• Related: Metrics collection (.github/metrics/)
• Dependencies: Existing metrics schema

Acceptance Criteria

• Workflow created and scheduled
• Metrics aggregated from existing sources
• Summary report generated and posted
• Historical archive maintained (e.g., .github/metrics/weekly/)
• Report format clear and actionable
• All tests pass

Reference

See workflow standards audit: .github/reports/audits/workflow-standards-audit-2026-05-31.md

[linear-code]

LS-811