fix(behaviours): separate React component from vanilla JS behaviours

- Create separate export path for BehavioursLoader React component
- Vanilla behaviours: @fergusbisset/nhs-fdp-design-system/behaviours
- React component: @fergusbisset/nhs-fdp-design-system/behaviours/react
- Exclude .tsx files from esbuild behaviours bundle
- Add Vite build step for React behaviours module
- Update all documentation and examples with new import path

Fixes 'Module not found' error when importing BehavioursLoader in Next.js

Author: Fergus Bisset

config/vite.behaviours.config.ts

@@ -0,0 +1,25 @@
+import { defineConfig } from 'vite';
+import react from '@vitejs/plugin-react';
+import { resolve } from 'path';
+
+// Build the BehavioursLoader React component
+// This is separate from the vanilla behaviours bundle
+export default defineConfig({
+  plugins: [react()],
+  build: {
+    lib: {
+      entry: resolve(__dirname, '../src/behaviours/react.ts'),
+      formats: ['es'],
+      fileName: () => 'react.js',
+    },
+    outDir: 'dist/src/behaviours',
+    emptyOutDir: false, // Don't delete existing files (types are already there)
+    sourcemap: true,
+    rollupOptions: {
+      external: ['react', 'react/jsx-runtime'],
+      output: {
+        preserveModules: false,
+      },
+    },
+  },
+});