feat: add garage.toml support (#30)

config.yaml.example

@@ -40,6 +40,12 @@ auth:
     username: "admin"
     password: "changeme"
 
+  # Admin Token Authentication
+  # When enabled, users can log in using the Garage admin token
+  # Auto-enabled when no other auth method is configured (zero-config fallback)
+  token:
+    enabled: false # Set to true to explicitly enable, or leave all auth disabled for auto-enable
+
   # OIDC Configuration
   # NOTE: When OIDC is enabled, server.root_url is required for OAuth2 redirects
   # The redirect URL will be automatically constructed as: {root_url}/auth/oidc/callback