ci: weekly test suite analysis agent #14
Description
Add an agentic workflow that runs weekly to analyze the test suite for coverage gaps.
The agent should read the entire repo and identify meaningful test gaps across unit tests, e2e tests, and integration tests — untested code paths, missing scenarios, weak assertions, or anything that would improve confidence in the code.
Constraints:
- Max 2 issues per run
- No trivial or duplicate test suggestions
- No nit-only issues — bundle small gaps into meaningful improvements
- Include root cause analysis and repro steps where applicable
- Assign copilot to work on created issues
- If the test suite is already comprehensive, create no issues