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/pages/HomePage.tsx

@@ -89,6 +89,12 @@ export const HomePage = () => {
               <a href="#about" className="text-white/75 hover:text-white transition-colors">
                 About
               </a>
+              <a
+                href="/guide"
+                className="text-white/75 hover:text-white transition-colors"
+              >
+                Guide
+              </a>
               <button
                 onClick={handleSignup}
                 className="border border-primary-500/90 text-primary-500 hover:bg-primary-500/10 hover:border-primary-500 font-semibold py-2 px-6 rounded-lg transition-colors duration-300 focus:outline-none focus:ring-2 focus:ring-primary-500/50"
@@ -160,6 +166,12 @@ export const HomePage = () => {
               >
                 About
               </a>
+              <a
+                href="/guide"
+                className="block text-white/75 hover:text-white transition-colors py-2"
+              >
+                Guide
+              </a>
               <button
                 onClick={handleSignup}
                 className="w-full border border-primary-500/90 text-primary-500 hover:bg-primary-500/10 font-semibold py-2 px-6 rounded-lg transition-colors duration-300 focus:outline-none focus:ring-2 focus:ring-primary-500/50"

frontend/src/pages/__tests__/GuidePage.test.tsx

@@ -0,0 +1,98 @@
+import { render, screen } from '@testing-library/react';
+
+jest.mock('@auth0/auth0-react', () => ({
+  useAuth0: () => ({
+    isAuthenticated: false,
+    loginWithRedirect: jest.fn(),
+  }),
+}));
+
+jest.mock('react-router-dom', () => ({
+  useNavigate: () => jest.fn(),
+}));
+
+// Mock MUI Accordion to avoid jsdom layout issues
+jest.mock('@mui/material', () => {
+  const actual = jest.requireActual('@mui/material');
+  return {
+    ...actual,
+    Accordion: ({ children, expanded }: any) => (
+      <div data-testid="accordion" data-expanded={expanded}>
+        {children}
+      </div>
+    ),
+    AccordionSummary: ({ children }: any) => <div>{children}</div>,
+    AccordionDetails: ({ children }: any) => <div>{children}</div>,
+  };
+});
+
+jest.mock('@mui/icons-material/ExpandMore', () => ({
+  __esModule: true,
+  default: () => <span data-testid="expand-icon" />,
+}));
+
+import { GuidePage } from '../GuidePage/GuidePage';
+import { guideSections } from '../GuidePage/guideTypes';
+
+describe('GuidePage', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it('renders page heading and subheading', () => {
+    render(<GuidePage />);
+    expect(screen.getByText('User Guide')).toBeInTheDocument();
+    expect(
+      screen.getByText(/Precision Vehicle Management/)
+    ).toBeInTheDocument();
+  });
+
+  it('renders all 10 section headings', () => {
+    render(<GuidePage />);
+
+    const expectedHeadings = [
+      '1. Getting Started',
+      '2. Dashboard',
+      '3. Vehicles',
+      '4. Fuel Logs',
+      '5. Maintenance',
+      '6. Gas Stations',
+      '7. Documents',
+      '8. Settings',
+      '9. Subscription Tiers and Pro Features',
+      '10. Mobile Experience',
+    ];
+
+    expectedHeadings.forEach((heading) => {
+      expect(screen.getByRole('heading', { name: heading })).toBeInTheDocument();
+    });
+  });
+
+  it('renders TOC with correct section titles', () => {
+    render(<GuidePage />);
+
+    guideSections.forEach((section) => {
+      const matches = screen.getAllByText(section.title);
+      expect(matches.length).toBeGreaterThanOrEqual(1);
+    });
+  });
+
+  it('renders navigation bar with Guide link highlighted', () => {
+    render(<GuidePage />);
+
+    const guideLinks = screen.getAllByText('Guide');
+    expect(guideLinks.length).toBeGreaterThanOrEqual(1);
+  });
+
+  it('renders GuideScreenshot components with loading="lazy"', () => {
+    render(<GuidePage />);
+
+    const images = document.querySelectorAll('img[loading="lazy"]');
+    expect(images.length).toBeGreaterThan(0);
+  });
+
+  it('renders footer with copyright', () => {
+    render(<GuidePage />);
+    expect(screen.getByText(/FB Technologies LLC/)).toBeInTheDocument();
+  });
+});