feat(i18n): tools + landing page + doorstop generator in English

Phase 1 of full English translation:
- generate_doorstop_items.py: all 55 items (SG/SYS/SWE/SA/SWA) rewritten in English
- generate_landing_page.py: full UI labels, KPI cards, section headings in English
- traceability.py: docstring, error messages, HTML headers in English
- generate_test_report.py: report content + table headers in English
- All 55 markdown items in safety/sg/, reqs/, arch/ regenerated in English

Still to come:
- demo-epb filled Word docs (PID, plans, safety, manuals, audit artefacts)
- Code comments + test names + CI workflow step names
- README + dev-process repo templates

arch/swe/SWA-008.md

@@ -13,11 +13,12 @@ asil: QM
 
 # SWA-008: Diagnostic Manager
 
-## Verantwortung
+## Responsibility
 
-UDS-Diagnose nach ISO 14229: ReadDTC, ReadDataByIdentifier, RoutineControl.
+UDS diagnostics per ISO 14229: ReadDTC, ReadDataByIdentifier,
+RoutineControl.
 
-## Schnittstellen (Provided)
+## Provided interfaces
 
 ```c
 Status diag_init(void);