docs: update all documentation for v0.2.4 release

Updated all documentation to reflect current state:

Version Updates:
- Updated root README.md from v0.2.0 to v0.2.4 in installation instructions
- Updated "Latest release" badge to v0.2.4
- Updated CHANGELOG.md with v0.2.1, 0.2.2, 0.2.3, and 0.2.4 entries
- Added version comparison links for all releases

URL Migrations:
- Fixed all GitHub badge URLs from cpfarhood to privilegedescalation org
- Updated plugin README.md repository URL placeholder
- Ensured all references use privilegedescalation/headlamp-sealed-secrets-plugin

Changelog Additions:
- v0.2.4: Icon loading fix (Material-UI → Iconify)
- v0.2.3: Superseded by v0.2.4 (checksum mismatch note)
- v0.2.2: SDK downgrade to fix React context errors
- v0.2.1: Removed invalid main field from package.json

All version numbers, checksums, and URLs are now consistent across:
- package.json: 0.2.4
- artifacthub-pkg.yml: 0.2.4
- README.md: 0.2.4
- CHANGELOG.md: 0.2.4
- GitHub releases: v0.2.4

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

headlamp-sealed-secrets/README.md

@@ -45,7 +45,7 @@ npm install -g headlamp-sealed-secrets
 
 #### Option 2: Build from Source
 ```bash
-git clone <repository-url>
+git clone https://github.com/privilegedescalation/headlamp-sealed-secrets-plugin
 cd headlamp-sealed-secrets
 npm install
 npm run build