chore: bump version to 0.2.0-dev.1

Release dev preview version with drawer-based namespace navigation.

Changes:
- Version bumped to 0.2.0-dev.1 in package.json
- Added prerelease: true flag in artifacthub-pkg.yml
- Updated archive URL to v0.2.0-dev.1
- Added [DEV PREVIEW] prefix to description
- Checksum placeholder (will be updated by release workflow)

This is a development release for testing the new drawer navigation
pattern before merging to main.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "headlamp-polaris-plugin",
-  "version": "0.1.6",
+  "version": "0.2.0-dev.1",
   "description": "Headlamp plugin for Fairwinds Polaris audit results",
   "scripts": {
     "start": "headlamp-plugin start",