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

reqs/swe/SWE-022.md

@@ -1,7 +1,7 @@
 ---
 active: true
 derived: false
-header: 'Stillstands-Erkennung aus Wheel Speeds'
+header: 'Standstill detection from wheel speeds'
 level: 1.22
 normative: true
 reviewed: null
@@ -12,6 +12,6 @@ links:
 asil: B
 ---
 
-# SWE-022: Stillstands-Erkennung aus Wheel Speeds
+# SWE-022: Standstill detection from wheel speeds
 
-Stillstand ist erkannt, wenn alle 4 Wheel-Speed-Signale fuer mindestens 200 ms unter 0.5 km/h liegen.
+Standstill is detected when all 4 wheel-speed signals stay below 0.5 km/h for at least 200 ms.