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/swe/SWE-006.md

@@ -1,7 +1,7 @@
 ---
 active: true
 derived: false
-header: 'Aktoren in Release-Position fahren'
+header: 'Drive actuators into release position'
 level: 1.6
 normative: true
 reviewed: null
@@ -10,6 +10,6 @@ links:
 asil: B
 ---
 
-# SWE-006: Aktoren in Release-Position fahren
+# SWE-006: Drive actuators into release position
 
-Der Actuator-Driver muss beide Aktoren parallel in Release-Position fahren. Maximalzeit: 1200 ms. Bei Timeout DTC setzen.
+The Actuator Driver must drive both actuators in parallel into the release position. Maximum time: 1200 ms. On timeout, set a DTC.