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-007.md

@@ -13,15 +13,15 @@ asil: QM
 
 # SWA-007: Display Manager
 
-## Verantwortung
+## Responsibility
 
-Steuert LED am EPB-Schalter und CAN-Status-Frame an das Kombi-Display.
-Empfaengt Status vom Apply-Controller.
+Drives the LED on the EPB switch and the CAN status frame to the
+instrument cluster. Receives status from the apply controller.
 
-## Schnittstellen (Provided)
+## Provided interfaces
 
 ```c
 Status display_init(void);
 void   display_set_status(EpbStatus s);
-void   display_step_20ms(void);  // 50 Hz CAN-Frame
+void   display_step_20ms(void);  // 50 Hz CAN frame
 ```