Lukas
2db635ae19
**Problem:** Broad exception handlers created fragility where adding a new DomainError subclass without explicit registration would silently fall through to the generic exception handler, losing the specific error_code and metadata. **Solution:** 1. Import DomainError in main.py for explicit handler registration 2. Fix type hints in exception handlers from 'Exception' to specific types - NotFoundError handler now typed as 'NotFoundError' - BadRequestError handler now typed as 'BadRequestError' - ConflictError handler now typed as 'ConflictError' - DomainError handler now typed as 'DomainError' - ServiceUnavailableError handler now typed as 'ServiceUnavailableError' 3. Add DomainError as an explicit catch-all handler in the registration chain - Positioned after specific handlers, before HTTPException - Any unregistered DomainError subclass now gets correct error_code + metadata 4. Document the exception handler hierarchy with detailed comments 5. Update Backend-Development.md with handler hierarchy documentation 6. Update Architekture.md section 2.2 with exception handler details 7. Fix test expectations in test_main.py to verify ErrorResponse format **Impact:** Any new DomainError subclass now automatically gets correct HTTP 500 status, error_code, and metadata - even if developer forgets explicit handler. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>