docs: standardize license to Apache-2.0 and update version references

- Change license from MIT to Apache-2.0 across all documentation to match package.json
- Update all version references from v0.3.4/v0.3.5 to v0.3.10
- Update tarball filenames from headlamp-polaris-plugin-*.tar.gz to polaris-0.3.10.tar.gz
- Update README.md license badge
- Update artifacthub-pkg.yml license field

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

docs/DOCUMENTATION_STANDARDIZATION_PLAN.md

@@ -54,7 +54,7 @@ README.md              # Main entry point with badges, quick links
 CHANGELOG.md           # Keep a Changelog format, semantic versioning
 CONTRIBUTING.md        # Development workflow, branching, PR process
 SECURITY.md            # Security model, vulnerability reporting, RBAC
-LICENSE               # MIT License
+LICENSE               # Apache-2.0 License
 package.json          # Plugin metadata
 ```