feat(i18n): remaining German comments + CI strings in English

Final residual translations found in code/comments/CI:
- .doorstop.yml: config comments, traceability mapping comments
- Doxyfile: header comment
- tools/render_plantuml.py: docstring
- tools/generate_test_report.py: docstring
- tests/unit_test_framework.h: doxygen brief + body
- tests/unit/test_safety_manager.c: section comment
- src/stubs/*.h: doxygen briefs for diag/display/inclinometer/logger/service/wheel-speed
- .gitea/workflows/release.yml: release notes 'Statische Analyse' + deploy error message

tests/unit/test_safety_manager.c

@@ -205,7 +205,7 @@ static void test_hillhold_armed_to_idle_if_grade_drops(void)
     TEST_END();
 }
 
-/* ---- Mutually exclusive: nicht in beiden Modi gleichzeitig ---- */
+/* ---- Mutually exclusive: never in both modes at once ---- */
 
 /* ---- Drive-Away-Assist (SWE-011 + SWE-012) ---- */