docs: update tracker for merged feat/test-coverage-visibility (Stage 4D)

- Update current status to Stage 4D complete (Stage 4 complete)

- Add feat/test-coverage-visibility slice entry with coverage baseline

- Set next branch to feat/android-app-shell (Stage 5A)

docs/development/build_execution_tracker.md

@@ -2,10 +2,10 @@
 
 ## Current status
 
-- main baseline updated through: flutter-cicd (Stage 4C complete)
-- main baseline commit: merge of `feat/flutter-cicd` (2026-05-22)
-- next branch: feat/test-coverage-visibility (Stage 4D)
-- current stage: Stage 4 — Platform foundations and cross-platform readiness
+- main baseline updated through: test-coverage-visibility (Stage 4D complete — Stage 4 complete)
+- main baseline commit: merge of `feat/test-coverage-visibility` (2026-05-22)
+- next branch: feat/android-app-shell (Stage 5A)
+- current stage: Stage 5 — Android application foundation
 
 ## Slice tracker
 
@@ -141,3 +141,20 @@
 - tests: passed (20/20 core, 41/41 design_system, 294/294 feature_wordpress, 24/24 kell_web — 379 total)
 - analyze: passed (dart analyze — no issues found across all 8 packages/apps)
 - brief updated: yes
+
+### feat/test-coverage-visibility
+
+- status: merged to main
+- date: 2026-05-22
+- inspection: complete
+- implementation: complete
+- files changed:
+  - `.forgejo/workflows/flutter-test.yml` — enhanced to run flutter test --coverage, parse lcov.info, report per-package line coverage percentages in aggregate summary table
+  - `kell_creations_apps/tools/collect_coverage.sh` — new local coverage helper script with summary table
+  - `kell_creations_apps/tools/README.md` — documented collect_coverage.sh script
+  - `.gitignore` — added coverage/ directories
+  - `docs/development/master_development_brief.md` — marked Stage 4D complete, documented baseline coverage table, updated next branch to Stage 5A, partially resolved improvement #5
+- tests: passed (20/20 core, 41/41 design_system, 294/294 feature_wordpress, 24/24 kell_web — 379 total)
+- analyze: passed
+- coverage baseline: core 85.7%, design_system 100.0%, feature_wordpress 84.7%, kell_web 54.1%, overall 78.4%
+- brief updated: yes