feat(health)!: promote to v1.0.0 — configurable check timeout via NewHandlerWithConfig

Add Config struct and NewHandlerWithConfig(logger, cfg, checks...) constructor.
Config.CheckTimeout sets the per-request deadline for all health checks; zero
value defaults to 5 seconds. NewHandler remains unchanged as a backward-compatible
wrapper. API committed as stable.

CHANGELOG.md

@@ -5,6 +5,22 @@ 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
+
+### Added
+
+- `Config` struct — `CheckTimeout time.Duration`; zero value defaults to 5 seconds.
+- `NewHandlerWithConfig(logger Logger, cfg Config, checks ...Checkable) http.Handler` —
+  constructor with explicit configuration. `NewHandler` is now a backward-compatible
+  wrapper that calls `NewHandlerWithConfig` with zero `Config`.
+
+### Unchanged
+
+All existing API (`Level`, `LevelCritical`, `LevelDegraded`, `Checkable`, `Logger`,
+`ComponentStatus`, `Response`, `NewHandler`) is API-compatible with v0.9.0.
+
+[1.0.0]: https://code.nochebuena.dev/go/health/releases/tag/v1.0.0
+
 ## [0.9.0] - 2026-03-18
 
 ### Added