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/sys/SYS-002.md

@@ -1,7 +1,7 @@
 ---
 active: true
 derived: false
-header: 'Apply auf Fahrer-Anforderung'
+header: 'Apply on driver request'
 level: 1.2
 normative: true
 reviewed: null
@@ -11,6 +11,6 @@ links:
 asil: D
 ---
 
-# SYS-002: Apply auf Fahrer-Anforderung
+# SYS-002: Apply on driver request
 
-Bei Betaetigung des EPB-Schalters in Apply-Richtung muss das System innerhalb von 800 ms die Parkbremse anlegen, sofern die Voraussetzungen erfuellt sind (Stillstand oder Geschwindigkeit unter 5 km/h). Sicherheitsziel: SG-01.
+On apply-direction actuation of the EPB switch, the system must engage the parking brake within 800 ms, provided the preconditions are met (standstill or vehicle speed below 5 km/h). Safety goal: SG-002.