First-pass URL encoding: test a harmless parameter

Before encoding real inputs, build a URL with a harmless parameter containing a space, ampersand, plus sign, and Unicode character. Verify that the receiver reads it back exactly. Use a URL builder or the correct component encoder instead of escaping the entire URL as plain text. Check for double encoding by inspecting %25 sequences. This small test establishes the encoding path without putting secrets into a third-party tool.