chore(release): prepare v0.1.0 for crates.io

- bump version to 0.1.0; add crates.io metadata (include list, homepage, rust-version)
- add .github/workflows/release.yml: on tag v* → publish to crates.io + GitHub Release with binaries
- README: absolute links/images and badges so it renders on crates.io; add install section
- CHANGELOG: 0.1.0

CHANGELOG.md

@@ -3,7 +3,7 @@
 All notable changes to this project are documented here.
 The format is based on [Keep a Changelog](https://keepachangelog.com/).
 
-## [Unreleased]
+## [0.1.0] - 2026-06-30
 
 ### Added
 - **Embedded admin web console** at `/admin` — a build-free single-page app compiled