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

arch/sys/SA-002.md

@@ -1,7 +1,7 @@
 ---
 active: true
 derived: false
-header: 'Aktoren (Caliper-Motoren)'
+header: 'Actuators (calliper motors)'
 level: 1.2
 normative: true
 reviewed: null
@@ -13,25 +13,25 @@ links:
 asil: D
 ---
 
-# SA-002: Aktoren (Caliper-Motoren)
+# SA-002: Actuators (calliper motors)
 
-## Verantwortung
+## Responsibility
 
-Zwei elektromechanische Aktoren an den hinteren Bremssaetteln klemmen
-und loesen die Bremsbelaege. Geliefert (Annahme): kommerzielles Bauteil
-eines Tier-1-Lieferanten.
+Two electromechanical actuators on the rear callipers clamp and
+release the brake pads. Supplied (assumption): commercial component
+from a Tier-1 supplier.
 
-## Schnittstellen
+## Interfaces
 
-| Schnittstelle | Typ          | Bemerkung                         |
-|---------------|--------------|-----------------------------------|
-| Power         | 12 V, PWM    | bidirektional fuer Apply/Release  |
-| Strom-Shunt   | Analog       | wird in der ECU abgegriffen       |
+| Interface     | Type         | Notes                           |
+|---------------|--------------|---------------------------------|
+| Power         | 12 V, PWM    | bidirectional for apply/release |
+| Current shunt | analog       | sampled inside the ECU          |
 
-## Nichtfunktionale Eigenschaften
+## Non-functional properties
 
-- Max. Klemmkraft: 20 kN
-- Apply-Zeit (0 → max): 600 ms
-- Strom (nominal): 4 A
-- Strom (Spitze): 30 A (kurzzeitig)
-- Temperaturbereich: -40°C bis +85°C
+- Max clamping force: 20 kN
+- Apply time (0 → max): 600 ms
+- Nominal current: 4 A
+- Peak current: 30 A (brief)
+- Temperature range: -40 °C to +85 °C