[zuudevs]

Summary

Continues roadmap milestone v0.8 by closing the URL/query correctness gap in REQ-HTTP-004 and strengthening URL validation.

Query parameter API

• adds Request::add_query_param(name, value)
• query parameter names/values are owned by Request
• repeated parameter names are preserved in insertion order
• existing raw query text in the URL is preserved
• appended parameters are serialized after the raw query
• spaces encode as %20 rather than +
• reserved characters are percent-encoded
• UTF-8 input is encoded byte-for-byte
• URI unreserved bytes remain unescaped

Redirect integration

The effective request URL now includes appended query parameters before redirect resolution. This keeps relative/query/fragment redirect behavior consistent with the actual request target while avoiding duplicate forwarding of the original query-parameter objects to redirected requests.

URL hardening

• validates raw path/query percent escapes as complete %HH sequences
• switches scheme comparison/normalization to ASCII-only handling
• validates bracketed hosts as real numeric IPv6 literals using the platform numeric parser
• accepts compressed IPv6 and IPv4-mapped IPv6 forms
• rejects malformed bracketed literals
• rejects unbracketed IPv6 as before
• rejects IPv6 zone identifiers for v1
• rejects percent-encoded authority text that the resolver does not decode in v1

Tests

Adds/extends coverage for:

• owned query parameter storage
• repeated parameter ordering
• existing raw query + appended parameters
• empty raw query marker
• spaces/reserved/unreserved characters
• UTF-8 byte encoding
• effective URL generation with fragments
• valid and malformed percent escapes
• valid bracketed IPv6 including IPv4-mapped form
• malformed/non-IPv6 bracketed hosts
• v1 zone-identifier rejection

Documentation

Updates the public API contract with the query-parameter and URL-validation behavior.

Scope

This PR does not alter TCP transport, response framing, connection reuse, or redirect status/method policy. v0.8 remains in progress after this PR; the next substep is the HTTP correctness review.