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

tools/generate_test_report.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 """
-Erzeugt einen Test-Summary-Report aus dem Output unserer Unit-Tests.
+Generate a test-summary report from the output of our unit tests.
 
 Reads the test-output file (build/test-output.txt) and produces:
 - build/test-report.md

tools/render_plantuml.py

@@ -1,9 +1,9 @@
 #!/usr/bin/env python3
 """
-Rendert alle @startuml ... @enduml Bloecke aus arch/**/*.md als SVG.
+Render all @startuml ... @enduml blocks from arch/**/*.md as SVG.
 
-Verwendet einen erreichbaren PlantUML-HTTP-Server (Default: www.plantuml.com).
-In CI kann die Server-URL ueber PLANTUML_SERVER ueberschrieben werden.
+Uses a reachable PlantUML HTTP server (default: www.plantuml.com).
+In CI the server URL can be overridden via PLANTUML_SERVER.
 
 Output: docs/diagrams/<file>-<index>.svg