fix(url): coerce WHATWG string arguments

[andrewtdiz]

Summary

• Closes node:url: coerce URL property setter values to strings #3056
• Closes node:url: coerce URLSearchParams method arguments #3057
• Closes node:url: coerce domainToASCII and domainToUnicode inputs #3059
• Routes URL property setters through the URL String(value) coercion path so booleans, nullish values, objects, and symbols match Node behavior.
• Routes URLSearchParams query and mutating method arguments through the same string coercion path, including explicit second arguments for has() and delete().
• Coerces domainToASCII() and domainToUnicode() inputs before IDNA conversion.
• Preserves adjacent setter validation for invalid protocol changes and out-of-range ports.
• Adds focused Node 24 parity fixtures for URL setters, URLSearchParams methods, and domain helper coercion.

Why Batched
These issues share the same WHATWG URL string-conversion boundary. Fixing them together keeps runtime FFI, codegen lowering, dynamic URL property assignment, and parity coverage consistent.

Verification

• Pre-fix focused parity reproduced all three gaps: PATH=/home/github-runner/actions-runner/externals/node24/bin:$PATH ./run_parity_tests.sh --suite node-suite --module url --filter coercion failed 0/3. Report: test-parity/reports/parity_report_20260531_025714.json
• Rebased full URL parity passed: PATH=/home/github-runner/actions-runner/externals/node24/bin:$PATH ./run_parity_tests.sh --suite node-suite --module url passed 61/61, 0 fail, 0 compile fail. Report: test-parity/reports/parity_report_20260531_032208.json
• RUSTC_WRAPPER= cargo check -p perry-runtime -p perry-codegen -p perry-hir -p perry-api-manifest -p perry passed with existing warnings.
• cargo fmt --all -- --check passed.
• ./scripts/check_file_size.sh passed.
• jq empty test-parity/known_failures.json passed.
• git diff HEAD~1..HEAD --check passed.

Known Limitations / Non-goals

• No broad WHATWG URL parser or IDNA algorithm rewrite beyond the coercion and adjacent setter validation covered here.
• No changes to legacy url.parse(), url.format(), or file URL path conversion behavior.