chore: add pr-body-ex2.md

.copilot-track/crawl/pr-body-ex2.md

@@ -0,0 +1,20 @@
+## Summary
+- Updated ai-track-docs/build-test.md with exact verified build and test commands for the chosen module (Squidex.Domain.Apps.Core.Model)
+- Added `Should_enumerate_all_configured_language_keys` to LanguagesConfigTests.cs — verifies `AllKeys` enumerates all configured language codes after sequential `Set` calls
+- Files touched: ai-track-docs/build-test.md, backend/tests/Squidex.Domain.Apps.Core.Tests/Model/Apps/LanguagesConfigTests.cs
+
+## Evidence
+- Tests/logs/metrics:
+  ```
+  dotnet test tests/Squidex.Domain.Apps.Core.Tests/Squidex.Domain.Apps.Core.Tests.csproj \
+    --filter "Should_enumerate_all_configured_language_keys"
+  → Passed! - Failed: 0, Passed: 1, Skipped: 0, Total: 1, Duration: 41 ms
+  ```
+
+## Risk & Rollback
+- Risk: low
+- Rollback: git revert 5a53520efda1d18c4b8332c578d146472bb71fff
+
+## Track
+- Level: Crawl
+- Exercise: Ex2