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-001.md

@@ -1,7 +1,7 @@
 ---
 active: true
 derived: false
-header: 'Kein ungewolltes Loesen der Parkbremse im Stillstand'
+header: 'No unintended release of the parking brake during standstill'
 level: 1.1
 normative: true
 reviewed: null
@@ -9,9 +9,9 @@ links: []
 asil: D
 ---
 
-# SG-001: Kein ungewolltes Loesen der Parkbremse im Stillstand
+# SG-001: No unintended release of the parking brake during standstill
 
-Die EPB darf sich im Stillstand des Fahrzeugs nicht ungewollt loesen. Abgeleitet aus HARA-Hazards H-01 (ungewolltes Loesen, Parkphase) und H-04 (Klemmkraftverlust im Hold).
+The EPB shall not unintentionally release while the vehicle is at a standstill. Derived from HARA hazards H-01 (unintended release during parking) and H-04 (clamping force loss in hold state).
 
 **FTTI:** 5 s (H-01) / 30 s (H-04).
-**Safe State:** APPLIED (Klemmkraft halten).
+**Safe state:** APPLIED (maintain clamping force).