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-006.md

@@ -12,12 +12,13 @@ asil: QM
 
 # SWA-006: Switch Debouncer
 
-## Verantwortung
+## Responsibility
 
-Software-Entprellung des EPB-Schalters. Liefert stabiles Apply / Release
-Signal an den Apply-Controller. Implementiert in `src/switch_debouncer.c`.
+Software debouncing of the EPB switch. Provides a stable apply /
+release signal to the apply controller. Implemented in
+`src/switch_debouncer.c`.
 
-## Schnittstellen (Provided)
+## Provided interfaces
 
 ```c
 Status switch_init(void);
@@ -25,8 +26,8 @@ void   switch_step_10ms(SwitchRaw raw);
 SwitchState switch_get_state(void);
 ```
 
-## Mapping auf Anforderungen
+## Mapping to requirements
 
-| Anforderung | Wie abgedeckt |
-|-------------|---------------|
-| SWE-025 | 50ms Debounce-Logik |
+| Requirement | How covered |
+|-------------|-------------|
+| SWE-025 | 50 ms debounce logic |