fix: loyalty sidebar menu label and active state highlighting

- Rename menu item IDs to match URL last segments (terminal, cards,
  stats) so the sidebar active state comparison works correctly
- Change "Dashboard" label to "Terminal" for the loyalty terminal page
- Point menu route directly to /loyalty/terminal (skip redirect)
- Add "terminal" translation key in all locale files (en, de, fr, lb)

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

app/modules/loyalty/config.py

@@ -43,7 +43,7 @@ class ModuleConfig(BaseSettings):
     # QR code settings
     qr_code_size: int = 300  # pixels
 
-    model_config = {"env_prefix": "LOYALTY_", "env_file": ".env", "extra": "ignore"}
+    model_config = {"env_prefix": "LOYALTY_"}
 
 
 # Export for auto-discovery