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>

typedoc.json

@@ -0,0 +1,26 @@
+{
+  "$schema": "https://typedoc.org/schema.json",
+  "entryPoints": [
+    "src/lib/crypto.ts",
+    "src/lib/controller.ts",
+    "src/lib/validators.ts",
+    "src/lib/retry.ts",
+    "src/lib/rbac.ts",
+    "src/types.ts",
+    "src/hooks/useSealedSecretEncryption.ts",
+    "src/hooks/usePermissions.ts",
+    "src/hooks/useControllerHealth.ts"
+  ],
+  "out": "docs/api-reference/generated",
+  "name": "Headlamp Sealed Secrets API",
+  "exclude": ["**/*.test.ts", "**/*.test.tsx", "**/test-setup.ts"],
+  "excludePrivate": true,
+  "excludeProtected": true,
+  "excludeExternals": true,
+  "plugin": ["typedoc-plugin-markdown"],
+  "readme": "none",
+  "githubPages": false,
+  "disableSources": false,
+  "includeVersion": true,
+  "sort": ["source-order"]
+}