chore: Woodpecker CI entfernt — nur noch Gitea Actions

Woodpecker wird nicht mehr verwendet. Wir migrieren vollstaendig
auf Gitea Actions (gitea.meghsakha.com).

Entfernt:
- woodpecker-server + woodpecker-agent Container (docker-compose.yml)
- woodpecker_data Volume
- backend-core/woodpecker_proxy_api.py (SQLite-DB Proxy)
- admin-core/app/api/admin/infrastructure/woodpecker/route.ts
- admin-core/app/api/webhooks/woodpecker/route.ts
- .woodpecker/main.yml (alte CI-Pipeline-Konfiguration)

Bereinigt:
- ci-cd/page.tsx: Woodpecker-Tab + Status-Karte + State entfernt
- types/infrastructure-modules.ts: Woodpecker-Typen + API-Endpunkte
- DevOpsPipelineSidebar.tsx: Textbeschreibungen auf Gitea Actions
- dashboard/page.tsx: Woodpecker aus Service-Health-Liste
- sbom/page.tsx: Woodpecker aus SBOM-Liste
- navigation.ts: Beschreibung aktualisiert
- .env.example: WOODPECKER_* Variablen entfernt

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend-core/main.py

@@ -25,8 +25,6 @@ from email_template_api import (
 )
 from system_api import router as system_router
 from security_api import router as security_router
-from woodpecker_proxy_api import router as woodpecker_router
-
 # ---------------------------------------------------------------------------
 # Middleware imports
 # ---------------------------------------------------------------------------
@@ -106,7 +104,6 @@ app.include_router(system_router)               # already has paths defined in r
 
 # Security / DevSecOps dashboard
 app.include_router(security_router, prefix="/api")
-app.include_router(woodpecker_router, prefix="/api")
 
 # ---------------------------------------------------------------------------
 # Startup / Shutdown events