fix: 7 Bugs behoben – Backend+Frontend lauffähig getestet

Backend-Fixes:
- vehicles-Relation in Account-Model ergänzt (500er bei Auth)
- security.py: bcrypt direkt statt passlib (bcrypt 5.x-Kompatibilität)
- auth.py Login: selectinload(User.role) gegen Lazy-Loading-500er
- equipment_group.py: LocationRef-Import via TYPE_CHECKING

Frontend-Fixes:
- api.ts: Python-Docstring durch JS-Kommentar ersetzt
- AppLayout.tsx: AddressBook→Contact (existiert nicht in lucide-react)
- package.json: axios-Dependency ergänzt

Tests bestanden:
- Health 200, Register 201, Login 200, Projects CRUD 200, alle API-Listen 200
- tsc --noEmit: sauber, vite build: erfolgreich

backend/app/core/security.py

@@ -3,22 +3,22 @@
 from datetime import datetime, timedelta, timezone
 from typing import Any
 
+import bcrypt
 from jose import jwt
-from passlib.context import CryptContext
 
 from app.core.config import settings
 
-pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
-
 
 def verify_password(plain_password: str, hashed_password: str) -> bool:
     """Verify a plaintext password against a bcrypt hash."""
-    return pwd_context.verify(plain_password, hashed_password)
+    return bcrypt.checkpw(
+        plain_password.encode("utf-8"), hashed_password.encode("utf-8")
+    )
 
 
 def get_password_hash(password: str) -> str:
     """Hash a password using bcrypt."""
-    return pwd_context.hash(password)
+    return bcrypt.hashpw(password.encode("utf-8"), bcrypt.gensalt()).decode("utf-8")
 
 
 def create_access_token(subject: str | Any, expires_delta: timedelta | None = None) -> str: