feat: add guide navigation integration and tests (refs #203)

- Add Guide link to public nav bar (desktop + mobile) in HomePage
- Add Guide link to authenticated sidebar in Layout.tsx
- Add Guide link to HamburgerDrawer with window.location guard
- Add GuidePage integration tests (6 test scenarios)
- Remove old PDF user guide at public/docs/v2026-01-03.pdf

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

frontend/src/shared-minimal/components/mobile/HamburgerDrawer.tsx

@@ -20,6 +20,7 @@ import LocalGasStationRoundedIcon from '@mui/icons-material/LocalGasStationRound
 import DescriptionRoundedIcon from '@mui/icons-material/DescriptionRounded';
 import BuildRoundedIcon from '@mui/icons-material/BuildRounded';
 import SettingsRoundedIcon from '@mui/icons-material/SettingsRounded';
+import HelpOutlineRoundedIcon from '@mui/icons-material/HelpOutlineRounded';
 import { MobileScreen } from '../../../core/store/navigation';
 
 // iOS swipeable drawer configuration
@@ -41,6 +42,7 @@ interface MenuItem {
 // Menu items from bottom to top (reversed order in array for rendering)
 const menuItems: MenuItem[] = [
   { screen: 'Settings', label: 'Settings', icon: <SettingsRoundedIcon /> },
+  { screen: 'Guide' as MobileScreen, label: 'Guide', icon: <HelpOutlineRoundedIcon /> },
   { screen: 'Documents', label: 'Documents', icon: <DescriptionRoundedIcon /> },
   { screen: 'Maintenance', label: 'Maintenance', icon: <BuildRoundedIcon /> },
   { screen: 'Log Fuel', label: 'Log Fuel', icon: <LocalGasStationRoundedIcon /> },
@@ -57,6 +59,12 @@ export const HamburgerDrawer: React.FC<HamburgerDrawerProps> = ({
   const theme = useTheme();
 
   const handleNavigate = (screen: MobileScreen) => {
+    // Guide is a public route outside /garage/* shell
+    if (screen === ('Guide' as MobileScreen)) {
+      window.location.href = '/guide';
+      onClose();
+      return;
+    }
     onNavigate(screen);
     onClose();
   };