feat: add semantic-release for automated versioning and help dialog

- Set up semantic-release with zero-touch CI pipeline on push to main
- Add version sync script to keep all package.json files and APP_VERSION
  constant in sync automatically
- Consolidate Docker publishing into single tag-triggered workflow that
  pushes to both Docker Hub and ghcr.io with semver tags
- Add help dialog with keyboard shortcuts, getting started guide, and
  resource links
- Sync all versions to 0.2.1 to match Docker Hub latest

packages/ai/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@stirling-image/ai",
-  "version": "0.0.1",
+  "version": "0.2.1",
   "private": true,
   "type": "module",
   "main": "./src/index.ts",