feat(Header): add SSR-safe auto-initialization to HeaderServer

- Add inline <script> tag to HeaderServer for self-initialization
- Script uses document.currentScript.previousElementSibling to find header
- Dynamic import of headerBehaviour module for overflow handling
- No 'use client' directive needed - pure server component
- Progressive enhancement: header functional without JS, enhanced with JS
- Wraps header and script in React Fragment for proper JSX structure

Related: Removed BehavioursLoader (requires 'use client')
Related: Created InitBehaviours using Next.js Script component

Author: Fergus Bisset

.npmrc

@@ -0,0 +1,9 @@
+# Project-specific npm configuration
+# GitHub Packages registry configuration
+registry=https://npm.pkg.github.com/
+@fergusbisset:registry=https://npm.pkg.github.com/
+
+# Note: 'always-auth' is deprecated in npm 10+
+# Authentication is now handled via .npmrc auth tokens
+# If you need authentication, add: //npm.pkg.github.com/:_authToken=${GITHUB_TOKEN}
+

README.md

@@ -146,7 +146,7 @@ nhs-fdp-design-system/
 
 Validation gates after SPC changes
 
-- Build: `npm run build:parity`
+- Build: `npm run build:parity` (or `npm run build:quiet` for cleaner output)
 - Tests (components): `npm run test:components` (expect one known non‑SPC failure in AriaTabsDataGrid)
 - SSR tests: `npm run test:ssr-components`
 - Lint & types: `npm run lint` and `npm run typecheck`
@@ -220,6 +220,12 @@ npm run storybook
 ### Available Scripts
 
 ```bash
+# Build
+npm run build                  # Full production build (alias for build:parity)
+npm run build:parity           # Complete build with all verification steps
+npm run build:quiet            # Clean build output (filters npm warnings)
+npm run build:fast             # Quick dev build (skips some verification)
+
 # Design tokens
 npm run build:tokens           # Build design tokens (smart rebuild)