fix: prevent double ?? in URL when using query params

[densetsuuu]

Problem

Calling urlFor('route', null, { qs: { var: 'hi' } }) produces /route??var=hi instead of /route?var=hi.

Root cause

buildSearchParams in packages/core/src/client/serializer.ts returned the query string with a leading ?. However, createURL in @adonisjs/http-server
already prepends one, resulting in a double ??.

Fix

Remove the ? prefix from buildSearchParams return value, so it returns a bare query string (foo=bar instead of ?foo=bar). This is consistent with thesearchParamsStringifier contract expected by @adonisjs/http-server.

Changes

• packages/core/src/client/serializer.ts — remove leading ? from return value
• packages/core/tests/serializer.spec.ts — update all expectations to match new output
• packages/core/tests/client_extras.spec.ts — add non-regression test that calls urlFor with qs and asserts no ?? in the resulting URL

Non-regression test

The new test in client_extras.spec.ts exercises the exact bug scenario end-to-end through urlFor. It was verified to fail before the fix and pass after.

[Julien-R44]

tié le goat mon sang