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-003.md

@@ -1,7 +1,7 @@
 ---
 active: true
 derived: false
-header: 'Release auf Fahrer-Anforderung'
+header: 'Release on driver request'
 level: 1.3
 normative: true
 reviewed: null
@@ -10,6 +10,6 @@ links:
 asil: B
 ---
 
-# SYS-003: Release auf Fahrer-Anforderung
+# SYS-003: Release on driver request
 
-Bei Betaetigung des EPB-Schalters in Release-Richtung muss das System die Parkbremse loesen, sofern die folgenden Voraussetzungen erfuellt sind: Motor laeuft, Fahrer betaetigt Bremspedal, Gang ist eingelegt. Maximalzeit fuer Loesen: 1500 ms.
+On release-direction actuation of the EPB switch, the system must release the parking brake provided the following preconditions are met: engine running, driver pressing the brake pedal, a gear is engaged. Maximum release time: 1500 ms.