Complete reviews + fix Navigation from user feedback

- Promote all 11 atoms, 6 molecules, 1 organism from review → done
- Navigation: grey bg (surface.subtle), real FA logo SVGs, add Provider Portal
- Navigation: remove mobileTrailing prop and MobilePriceTracker story
- Add staticDirs to Storybook config for brand assets

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.storybook/main.ts

@@ -13,6 +13,7 @@ const config: StorybookConfig = {
   docs: {
     autodocs: 'tag',
   },
+  staticDirs: ['../brandassets'],
   viteFinal: async (config) => {
     // Inherit aliases from vite.config.ts automatically via react-vite framework
     return config;