feat(i18n): full English translation of demo-epb

Phase 2 of the English translation:

Word documents (filled, EPB-specific):
- 8 plans (PID, PM, QA, SWE, Test, Project Manual, CM, RM)
- 6 safety docs (HARA, Safety Case, FMEDA, MISRA Compliance,
  Verification Report, Tool Qualification Cppcheck)
- 2 manuals (User, Service)
- 3 audit artefacts (Review minutes, NC-001, MISRA-REC-001)
- All regenerated via pandoc from English markdown sources

Code, tests, headers:
- All file headers, struct comments, function docstrings in English
- All test names (TEST_BEGIN strings) translated
- Inline comments translated
- 46 tests still green after translation

CI workflows:
- All step names in English
- Step descriptions, comments, release notes template in English

README.md fully rewritten in English with proper guided tour.

Phase 3 (still pending): dev-process repo templates + toolstack/setup docs.

docs/plans-md/Test-Plan.md

@@ -1,63 +1,63 @@
-# Test-Plan
+# Test Plan
 
-| Feld            | Wert                                |
+| Field           | Value                                |
 |-----------------|--------------------------------------|
-| Projekt         | demo-epb                             |
-| Datum           | 2026-05-11                           |
+| Project         | demo-epb                             |
+| Date            | 2026-05-11                           |
 | Version         | 1.0                                  |
-| Status          | Freigegeben                          |
+| Status          | Released                             |
 
 ---
 
-## 1. Teststrategie
+## 1. Test strategy
 
-Test-First fuer alle Demo-Komponenten. Jede Anforderung erhaelt mindestens einen Test (`@reqs` Tag im Test). Coverage-Ziele wie im SWE-Plan Abschnitt 8.
+Test-first for all demo components. Every requirement has at least one test (`@reqs` tag in the test). Coverage targets as in the SWE Plan section 8.
 
-## 2. Teststufen
+## 2. Test levels
 
-| Stufe         | Scope              | Tool       | Umgebung   | Demo-Status |
-|---------------|--------------------|------------|------------|-------------|
-| Unit          | Funktionen / Module| CppUTest   | Host x86   | Vorhanden   |
-| Integration   | Modulzusammenspiel | CppUTest   | Host x86   | TBD         |
-| System        | End-to-end         | manuell    | SiL / HiL  | nicht im Demo |
-| Abnahme       | Kundenabnahme      | manuell    | HiL / KFZ  | nicht im Demo |
+| Level         | Scope              | Tool       | Environment | Demo status   |
+|---------------|--------------------|------------|-------------|---------------|
+| Unit          | Functions / modules| CppUTest   | host x86    | Available     |
+| Integration   | Module interaction | CppUTest   | host x86    | TBD           |
+| System        | End-to-end         | manual     | SiL / HiL   | not in demo   |
+| Acceptance    | Customer acceptance| manual     | HiL / vehicle | not in demo |
 
-## 3. Test-Verwaltung
+## 3. Test management
 
-- Tests liegen in `tests/unit/` (eine Datei pro Modul)
-- Test-Datei enthaelt `@reqs` Tag mit den abgedeckten Anforderungs-IDs
-- Test-Lauf erfolgt automatisch in der CI bei jedem Push
-- Coverage-Report wird als CI-Artefakt unter `tests/results/coverage/` abgelegt
+- Tests live in `tests/unit/` (one file per module)
+- Each test file carries an `@reqs` tag with the covered requirement IDs
+- Tests run automatically in CI on every push
+- Coverage report is uploaded as a CI artefact under `tests/results/coverage/`
 
-## 4. Test-Auswahl je Komponente
+## 4. Test selection per component
 
-| Komponente         | ASIL | Test-Datei                          | Methodik                |
-|--------------------|------|--------------------------------------|--------------------------|
-| Apply Controller   | D    | tests/unit/test_apply_controller.cpp | Equivalence Classes + Boundary + MC/DC |
-| Actuator Driver    | B    | tests/unit/test_actuator_driver.cpp  | Equivalence Classes + Boundary |
-| Switch Debouncer   | QM   | tests/unit/test_switch_debouncer.cpp | Equivalence Classes      |
+| Component          | ASIL | Test file                            | Method                          |
+|--------------------|------|---------------------------------------|---------------------------------|
+| Apply Controller   | D    | tests/unit/test_apply_controller.c    | Equivalence classes + boundary + MC/DC |
+| Actuator Driver    | B    | tests/unit/test_actuator_driver.c     | Equivalence classes + boundary  |
+| Switch Debouncer   | QM   | tests/unit/test_switch_debouncer.c    | Equivalence classes              |
 
-## 5. Eingangs- und Abschlusskriterien
+## 5. Entry and exit criteria
 
-**Eingang fuer Testdurchfuehrung:**
-- Code kompiliert
-- Doorstop-Check gruen
-- Statische Analyse ohne kritische Findings
+**Entry to test execution:**
+- Code compiles
+- Doorstop check is green
+- Static analysis has no critical findings
 
-**Abschluss:**
-- Alle Tests gruen
-- Coverage-Ziel erreicht
-- Test-Report archiviert
+**Exit:**
+- All tests green
+- Coverage target reached
+- Test report archived
 
-## 6. Fehlerverwaltung
+## 6. Defect handling
 
-- Test-Fehlschlag = blockendes Issue
-- Issue wird ueber Gitea Issues angelegt, im PR referenziert
-- Schwere-Kategorisierung wie in QA-Plan Abschnitt 4
+- Test failure = blocking issue
+- Issue is filed via Gitea Issues, referenced in the PR
+- Severity classification per QA Plan section 4
 
 ## 7. Reporting
 
-Test-Reports werden automatisch erzeugt:
-- Konsolen-Output von CppUTest (TAP / JUnit XML)
-- Coverage-HTML aus lcov
-- Beides als CI-Artefakt unter `tests/results/`
+Test reports are generated automatically:
+- Console output of CppUTest (TAP / JUnit XML)
+- Coverage HTML from lcov
+- Both as CI artefacts under `tests/results/`