feat(gui): add discovery triage, network scan management, and approval workflow pages (M24)

Three new GUI surfaces closing the backend-to-frontend gap for V2:

- Discovery triage page: summary stats bar, DataTable with claim/dismiss
  actions, status/agent filters, collapsible scan history panel
- Network scan target management: CRUD with create modal, enable/disable
  toggle, Scan Now button, last scan results display
- Jobs page approval workflow: Approve/Reject buttons for AwaitingApproval
  jobs, rejection reason modal, pending approval banner with count,
  AwaitingApproval/AwaitingCSR added to status filter dropdown

Also adds 13 new frontend tests, 4 API types, 12 API client functions,
2 sidebar nav items, 2 routes, and discovery status badge styles.

Docs updated: README, architecture, quickstart, demo-advanced, CLAUDE.md,
roadmap. Version bumped to v2.0.4.

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

web/src/main.tsx

@@ -23,6 +23,8 @@ import AgentGroupsPage from './pages/AgentGroupsPage';
 import AuditPage from './pages/AuditPage';
 import ShortLivedPage from './pages/ShortLivedPage';
 import AgentFleetPage from './pages/AgentFleetPage';
+import DiscoveryPage from './pages/DiscoveryPage';
+import NetworkScanPage from './pages/NetworkScanPage';
 import './index.css';
 
 const queryClient = new QueryClient({
@@ -61,6 +63,8 @@ createRoot(document.getElementById('root')!).render(
                   <Route path="agent-groups" element={<AgentGroupsPage />} />
                   <Route path="audit" element={<AuditPage />} />
                   <Route path="short-lived" element={<ShortLivedPage />} />
+                  <Route path="discovery" element={<DiscoveryPage />} />
+                  <Route path="network-scans" element={<NetworkScanPage />} />
                 </Route>
               </Routes>
             </BrowserRouter>