feat(httputil)!: promote to v1.0.0 — bump xerrors and valid to v1, stabilize API

Bump xerrors to v1.0.1 and valid to v1.0.1. Go directive bumped to 1.26.
API committed as stable: Handle, HandleNoBody, HandleEmpty, HandlerFunc,
JSON, NoContent, and Error are unchanged from v0.10.0.

CHANGELOG.md

@@ -5,6 +5,21 @@ All notable changes to this module will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this module adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.0.0] - 2026-05-12
+
+### Changed
+
+- Go directive bumped from 1.25 to 1.26
+- `xerrors` dependency bumped to v1.0.1
+- `valid` dependency bumped to v1.0.1
+
+### Stabilization
+
+- API committed as stable. `Handle`, `HandleNoBody`, `HandleEmpty`, `HandlerFunc`,
+  `JSON`, `NoContent`, and `Error` are unchanged from v0.10.0.
+
+[1.0.0]: https://code.nochebuena.dev/go/httputil/compare/v0.10.0...v1.0.0
+
 ## [0.10.0] - 2026-03-25
 
 ### Changed