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-001.md

@@ -17,12 +17,12 @@ asil: D
 
 # SWA-001: Safety Manager
 
-## Verantwortung
+## Responsibility
 
-Hoechste Sicherheitsschicht. Erkennt Motor-Aus, aktiviert Hill-Hold,
-triggert Auto-Apply. Lebenswichtige Logik mit redundanter Pruefung.
+Highest safety layer. Detects engine-off, activates hill-hold,
+triggers auto-apply. Life-critical logic with redundant checks.
 
-## Statische Sicht
+## Static view
 
 ```plantuml
 @startuml
@@ -31,20 +31,20 @@ package "Safety Manager" {
   [Hill-Hold Logic]
   [Auto-Apply Logic]
 }
-[Safety Manager] ..> [Apply Controller] : Apply-Anforderung
+[Safety Manager] ..> [Apply Controller] : apply request
 [Wheel Speed Plausi] --> [Safety Manager] : v_vehicle
 [Inclinometer Filter] --> [Safety Manager] : grade
 @enduml
 ```
 
-## Schnittstellen (Provided)
+## Provided interfaces
 
 ```c
 Status safety_mgr_init(void);
 void   safety_mgr_step_50ms(const SafetyInputs* in);
 ```
 
-## Dynamisches Verhalten
+## Dynamic behaviour
 
 ```plantuml
 @startuml
@@ -58,16 +58,16 @@ AutoApplyTriggered --> Idle : applied
 @enduml
 ```
 
-## Ressourcen
+## Resources
 
 - Stack: <= 256 B
-- Worst-Case Timing: 200 us / Aufruf
+- Worst-case timing: 200 us per call
 
-## Mapping auf Anforderungen
+## Mapping to requirements
 
-| Anforderung | Wie abgedeckt |
-|-------------|---------------|
+| Requirement | How covered |
+|-------------|-------------|
 | SWE-007 | engine_off + v<0.5 in step_50ms |
-| SWE-008 | 2s-Filter und Trigger |
-| SWE-009 | Hill-Hold-Aktivierung |
-| SWE-010 | Brake-Released-Detektion |
+| SWE-008 | 2 s filter and trigger |
+| SWE-009 | hill-hold activation |
+| SWE-010 | brake-released detection |