fix: token validator lambda parameter mismatch in tests

The token_validator lambda in test setup was defined as `-> { true }`
(no parameters) but the authentication code calls it with a parameter
`token_validator.call(decoded)`. This caused a silent ArgumentError that
broke the authentication flow, causing the test to fail.

Fixed by changing the lambda to accept the decoded parameter:
`-> { true }` → `->(_decoded) { true }`

🤖 Generated with [Claude Code](https://claude.ai/code)

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

Author: Pepan

test/rack_transport_patch_test.rb

@@ -84,7 +84,7 @@ def setup_authentication_callbacks(mock_user, &user_capture)
       user_finder: lambda do |decoded|
         decoded[:user_id] == 123 ? mock_user : nil
       end,
-      token_validator: -> { true },
+      token_validator: ->(_decoded) { true },
       user_capture: user_capture
     }
   end