feat(frontend): add Projects, Agents, and Settings pages for enhanced project management

- Added routing and localization for "Projects" and "Agents" in `Header.tsx`.
- Introduced `ProjectAgentsPage` to manage and display agent details per project.
- Added `ProjectActivityPage` for real-time event tracking and approval workflows.
- Implemented `ProjectSettingsPage` for project configuration, including autonomy levels and repository integration.
- Updated language files (`en.json`, `it.json`) with new translations for "Projects" and "Agents".

frontend/src/components/layout/Header.tsx

@@ -99,6 +99,8 @@ export function Header() {
             <NavLink href="/dashboard" exact>
               {t('home')}
             </NavLink>
+            <NavLink href="/projects">{t('projects')}</NavLink>
+            <NavLink href="/agents">{t('agents')}</NavLink>
             {user?.is_superuser && <NavLink href="/admin">{t('admin')}</NavLink>}
           </nav>
         </div>