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

docs/traceability/matrix.json

@@ -7,7 +7,7 @@
     "sys": {
       "id": "SYS-001",
       "asil": "D",
-      "title": "Halten der Parkbremse im Stillstand"
+      "title": "Holding the parking brake at standstill"
     },
     "sa": [
       {
@@ -58,7 +58,7 @@
     "sys": {
       "id": "SYS-004",
       "asil": "D",
-      "title": "Auto-Apply bei Motor-Aus"
+      "title": "Auto-apply on engine off"
     },
     "sa": [
       {
@@ -97,7 +97,7 @@
     "sys": {
       "id": "SYS-002",
       "asil": "D",
-      "title": "Apply auf Fahrer-Anforderung"
+      "title": "Apply on driver request"
     },
     "sa": [
       {
@@ -158,7 +158,7 @@
     "sys": {
       "id": "SYS-005",
       "asil": "D",
-      "title": "Hill-Hold am Berg"
+      "title": "Hill-hold on an incline"
     },
     "sa": [
       {
@@ -209,7 +209,7 @@
     "sys": {
       "id": "SYS-007",
       "asil": "B",
-      "title": "Aktor-Stromueberwachung"
+      "title": "Actuator current monitoring"
     },
     "sa": [
       {
@@ -268,7 +268,7 @@
     "sys": {
       "id": "SYS-005",
       "asil": "D",
-      "title": "Hill-Hold am Berg"
+      "title": "Hill-hold on an incline"
     },
     "sa": [
       {
@@ -319,7 +319,7 @@
     "sys": {
       "id": "SYS-006",
       "asil": "B",
-      "title": "Auto-Release beim Anfahren (Drive-Away-Assist)"
+      "title": "Auto-release on drive-away (Drive-Away Assist)"
     },
     "sa": [
       {
@@ -370,7 +370,7 @@
     "sys": {
       "id": "SYS-002",
       "asil": "D",
-      "title": "Apply auf Fahrer-Anforderung"
+      "title": "Apply on driver request"
     },
     "sa": [
       {
@@ -431,7 +431,7 @@
     "sys": {
       "id": "SYS-003",
       "asil": "B",
-      "title": "Release auf Fahrer-Anforderung"
+      "title": "Release on driver request"
     },
     "sa": [
       {
@@ -487,7 +487,7 @@
     "sys": {
       "id": "SYS-008",
       "asil": "QM",
-      "title": "Service-Modus fuer Werkstatt"
+      "title": "Service mode for the workshop"
     },
     "sa": [
       {
@@ -523,7 +523,7 @@
     "sys": {
       "id": "SYS-009",
       "asil": "QM",
-      "title": "UDS-Diagnose"
+      "title": "UDS diagnostics"
     },
     "sa": [
       {
@@ -563,7 +563,7 @@
     "sys": {
       "id": "SYS-010",
       "asil": "QM",
-      "title": "HMI-Statusanzeige"
+      "title": "HMI status display"
     },
     "sa": [
       {