Keycloak-Nutzermanagement

What is new and why?

Dieses MR fügt eine vollständige Keycloak-Integration zum F13-Core-Microservice hinzu, um sichere Authentifizierung und Nutzermanagement zu ermöglichen. Die Integration umfasst:

• JWT-Token-Verifizierung für alle API-Endpoints (Chat, RAG, Summary, Feedback)
• WebSocket-Authentifizierung für Echtzeit-Kommunikation
• Konfigurierbare Audience-Validierung zur Sicherstellung der Token-Gültigkeit
• Docker-Compose-Stack mit Keycloak und PostgreSQL-Datenbank
• Test-Realm-Konfigurationen für die Entwicklungsumgebung
• Dependency Injection für Settings-Klasse
• Authentifizierungs-Tests und JWT-Golden-Tests

Related issues

Closes #31 (closed) #35 (closed)

Author's TODOs

• merged latest version of target branch (e.g., main or dev) into your branch
• check if SPDX identifier MPL-2.0 and Copyright-Text 2025 Land Baden-Württemberg <InnoLab@stm.bwl.de> exists in newly created and/or hasn't been deleted somehow in existing files
• adapted the readme
• Revised/new code parts have no # noqa directives
• Optional: Changelog adapted ([further information](https://f13-os.de/ mitmachen/contributing-guidelines/#release-planung-und-changelog))

Reviewer's TODOs

• Check if the Author did their checks well enough
• Tried out if the cause of the issue is solved as intended
• Check that code with old # noqa directives were revised
• Check that no new # noqa directives are included
• Optional: Changelog adapted (further information)

To keep in mind

• pre-commit used
• added logging output were necessary
• added/adjusted Errorhandling to avoid unwanted crashes and make proper debugging and testing possible
• Changelog has to be adapted before merging, at latest in the f13::inAbnahme step

Closes #31 (closed)