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-003.md

@@ -1,7 +1,7 @@
 ---
 active: true
 derived: false
-header: 'Schutz gegen Aktor-Ueberlast'
+header: 'Protection against actuator overload'
 level: 1.3
 normative: true
 reviewed: null
@@ -9,9 +9,9 @@ links: []
 asil: A
 ---
 
-# SG-003: Schutz gegen Aktor-Ueberlast
+# SG-003: Protection against actuator overload
 
-Das System muss Aktor-Motorschaeden durch Ueberstrom verhindern. Abgeleitet aus HARA-Hazard H-05.
+The system shall prevent actuator motor damage due to overcurrent. Derived from HARA hazard H-05.
 
 **FTTI:** 100 ms.
-**Safe State:** Aktor abschalten, DTC setzen.
+**Safe state:** Disable actuator, set DTC.