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

safety/sg/SG-002.md

@@ -1,7 +1,7 @@
 ---
 active: true
 derived: false
-header: 'Kein ungewolltes Festklemmen waehrend der Fahrt'
+header: 'No unintended clamping while driving'
 level: 1.2
 normative: true
 reviewed: null
@@ -9,9 +9,9 @@ links: []
 asil: D
 ---
 
-# SG-002: Kein ungewolltes Festklemmen waehrend der Fahrt
+# SG-002: No unintended clamping while driving
 
-Die EPB darf nicht waehrend der Fahrt ungewollt festklemmen. Abgeleitet aus HARA-Hazard H-02.
+The EPB shall not unintentionally clamp while the vehicle is moving. Derived from HARA hazard H-02.
 
 **FTTI:** 100 ms.
-**Safe State:** Aktor stop (kein Apply einleiten).
+**Safe state:** Actuator stop (do not initiate apply).