chore: move source to repo root and standardize config

Phase 1 — Structural overhaul:
- Move all source from headlamp-sealed-secrets/ subdirectory to repo root
- Delete 23 AI-generated docs, 8 pre-built tarballs, release snapshots dir
- Remove all working-directory refs from CI/release workflows
- Update install-plugin.sh and typedoc.json paths

Phase 2 — Config standardization:
- Create .eslintrc.js and .prettierrc.js (standard Headlamp configs)
- Remove inline eslintConfig/prettier from package.json (drop jsx-a11y, prettier extends)
- Rewrite tsconfig.json (package name extend, add compilerOptions.types)
- Create vitest.config.mts and vitest.setup.ts (standard from polaris)
- Replace headlamp-plugin CLI scripts with direct tool invocation
- Rewrite .gitignore with standard baseline

Phase 3 — MCP & Claude settings:
- Create .mcp.json with github/kubernetes/flux/playwright servers
- Create .claude/settings.local.json
- Remove 7 specialized agents, keep 3 meta-orchestration agents

Phase 4 — Documentation:
- Rewrite CLAUDE.md (remove subdirectory refs, standard format)
- Add ArtifactHub badge, Architecture section, standardized install methods to README.md
- Create CONTRIBUTING.md and SECURITY.md
- Fix pre-existing test bugs in validators.test.ts (isValidNamespace returns boolean,
  not ValidationResult; error message string mismatches)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.github/workflows/ci.yaml

@@ -20,32 +20,26 @@ jobs:
         with:
           node-version: '20'
           cache: 'npm'
-          cache-dependency-path: headlamp-sealed-secrets/package-lock.json
 
       - name: Install dependencies
-        working-directory: ./headlamp-sealed-secrets
         run: npm ci
 
       - name: Type-check
-        working-directory: ./headlamp-sealed-secrets
         run: npm run tsc
 
       - name: Lint
-        working-directory: ./headlamp-sealed-secrets
         run: npm run lint
 
       - name: Build plugin
-        working-directory: ./headlamp-sealed-secrets
         run: npx @kinvolk/headlamp-plugin build
 
       - name: Verify build artifacts
-        working-directory: ./headlamp-sealed-secrets
         run: |
           if [ ! -d "dist" ] || [ -z "$(ls -A dist)" ]; then
             echo "::error::dist directory is empty or missing"
             exit 1
           fi
-          echo "✓ Build artifacts verified"
+          echo "Build artifacts verified"
           ls -lh dist/
 
       - name: Upload build artifact (for inspection)
@@ -53,5 +47,5 @@ jobs:
         if: always()
         with:
           name: plugin-dist
-          path: headlamp-sealed-secrets/dist/
+          path: dist/
           retention-days: 7