fix: refine earth hud structure and bun startup flow

- refactor the /earth HUD into class-first CSS layers with dedicated base, hud, and toolbar responsibilities
- clean up Earth markup and runtime DOM hooks so shared panel, toolbar, tooltip, and status classes stay consistent after dynamic updates
- keep HUD scaling configurable through extracted constants and remove leftover legacy panel/toolbar styling paths
- make planet.sh self-bootstrap Bun and uv by prepending local runtime bins to PATH and auto-installing missing tools in fresh environments
- document Bun as the frontend package manager of record and sync repository version metadata to 0.24.1

frontend/package.json

@@ -1,7 +1,8 @@
 {
   "name": "planet-frontend",
-  "version": "0.24.0",
+  "version": "0.24.1",
   "private": true,
+  "packageManager": "bun@1",
   "dependencies": {
     "@ant-design/icons": "^5.2.6",
     "antd": "^5.12.5",