docs: prepare gem to first publication

Author: crow-rojas

CHANGELOG.md

@@ -1,5 +1,17 @@
-## [Unreleased]
+# CHANGELOG
 
-## [0.1.0] - 2025-08-29
+## [0.1.0] - 2025-09-10
 
-- Initial release
+### Added
+
+- Dev-only Rails engine with floating UI panel.
+- Minimal DSL: `panel`/`tab`/`action` with `param` support for `:string`, `:boolean`, `:integer`, `:selector`.
+- Selector return modes: `:value` (default), `:label`, `:both`.
+- Option `meta` passthrough for selectors and UI hint badge for current boolean state.
+- Auto-refresh of panel after running an action and remember last selector choice.
+- JSON pretty result viewer in the UI.
+
+### Internal
+
+- Registry, Executor, Middleware, basic controllers and assets pipeline.
+- Minitest suite and SimpleCov.