feat: implement user profile management and oauth/traefik integration

User Profile (US-004):
- Add authenticated profile endpoints (GET/PUT /users/me)
- Add avatar upload with file validation (PNG/JPEG, max 2MB)
- Create frontend profile page with edit form and avatar upload
- Update app shell to link to profile page

OAuth/Traefik Integration:
- Externalize all Authentik URLs to environment variables
- Add domain configuration (API_DOMAIN, WEB_DOMAIN, AUTHENTIK_DOMAIN)
- Create docker-compose.traefik.yml for reverse proxy deployment
- Update OAuth redirect/callback URLs to use configured domains
- Add VITE_APP_URL for frontend public URL configuration

Quality gates: pytest (50 passed), ruff, mypy, npm test (12 passed), typecheck, lint, build

apps/web/src/router.tsx

@@ -4,6 +4,7 @@ import { AppShell } from "./components/app-shell";
 import { ProtectedRoute } from "./components/protected-route";
 import { DashboardPage } from "./pages/dashboard";
 import { LoginRedirectPage, NotFoundPage, PlaceholderPage } from "./pages/placeholder";
+import { ProfilePage } from "./pages/profile";
 import { ProjectsPage } from "./pages/projects";
 
 export const AppRouter = () => {
@@ -22,6 +23,7 @@ export const AppRouter = () => {
         <Route path="projects" element={<ProjectsPage />} />
         <Route path="repositories" element={<PlaceholderPage title="Repositories" />} />
         <Route path="ssh-keys" element={<PlaceholderPage title="SSH Keys" />} />
+        <Route path="profile" element={<ProfilePage />} />
         <Route path="settings" element={<PlaceholderPage title="Settings" />} />
       </Route>
       <Route path="/404" element={<NotFoundPage />} />