test: Stage 5

Author: tzanko-matev

design-docs/test-suite-improvement-plan.status.md

@@ -14,11 +14,11 @@
 - ✅ Stage 4 – Python Unit Coverage: added `tests/python/unit/test_session_helpers.py`
   for facade utilities and introduced `tests/python/support` for shared
   fixtures; updated monitoring tests to use the helper directory builder.
-- 🚧 Stage 5 – CI & Coverage Instrumentation: CI now runs Rust and Python
-  suites in separate steps; coverage instrumentation plan still pending.
+- ✅ Stage 5 – CI & Coverage Instrumentation: CI now runs the split Rust/Python
+  test jobs plus a non-blocking coverage job that reuses `just coverage`, uploads
+  LCOV/XML/JSON artefacts, and posts a per-PR summary comment.
 - ⏳ Stage 6 – Cleanup & Documentation: not started.
 
 ## Next Actions
-1. Implement coverage collection (Just targets + CI artefacts) following the
-   drafted plan while keeping steps non-blocking initially.
-2. Evaluate report stability and prepare enforcement thresholds before Stage 6.
+1. Evaluate coverage report stability and prepare enforcement thresholds before
+   Stage 6.