Add Vitest coverage for erasure lanes, fleet evolution UI, and spread routes.

Cover Path Tracer RS lane hints, Calibrate erasure toggle, fleet role chips, atlas skips panel, and erasure_lanes help copy.

server/web/src/components/Fleet/AccessDepthPanel.test.tsx

@@ -200,6 +200,20 @@ describe('AccessDepthPanel', () => {
     expect(screen.getByText(/confidence 72%/i)).toBeInTheDocument();
   });
 
+  it('renders atlas skips block when failure atlas hard-skips tiers', async () => {
+    renderPanel(
+      mockAgent({ platform: 'windows', status: 'online' }),
+      parseAccessDepthDiagnostics({
+        tier_chain_order: ['exe_subprocess', 'ps_inmemory', 'cpu_inprocess'],
+        atlas_skips: [
+          { tier: 'ps_inmemory', condition: 'defender_on', reason: '5 failures with Defender on' },
+        ],
+      }),
+    );
+    expect(await screen.findByText('Atlas skips')).toBeInTheDocument();
+    expect(screen.getByText(/ps inmemory \(Defender on\)/i)).toBeInTheDocument();
+  });
+
   it('shows spread genealogy lineage when watermark present', async () => {
     renderPanel(
       mockAgent({

server/web/src/help/settingHelp.test.ts

@@ -179,4 +179,11 @@ describe('FIELD_HELP', () => {
     expect(FIELD_HELP.com_hijack_persist).toContain('CLSID');
     expect(FIELD_HELP.linux_lotl_mode).toContain('systemd-run');
   });
+
+  it('erasure_lanes describes Reed–Solomon shard encoding foundation', () => {
+    expect(FIELD_HELP.erasure_lanes).toMatch(/Reed.?Solomon/i);
+    expect(FIELD_HELP.erasure_lanes).toContain('erasure_lanes_enabled');
+    expect(FIELD_HELP.erasure_lanes).toMatch(/dns_txt|bits_curl|do_peer|wsus_cache_peer/);
+    expect(FIELD_HELP.erasure_lanes).toMatch(/Foundation only/i);
+  });
 });

server/web/src/pages/BuilderPage.test.tsx

@@ -684,6 +684,28 @@ describe('BuilderPage', () => {
     preflightSpy.mockRestore();
   });
 
+  it('selects fleet role seeder chip in advanced spread section', async () => {
+    const buildSpy = vi.spyOn(api, 'buildAgent');
+    const user = userEvent.setup();
+    renderBuilder();
+    await screen.findByRole('heading', { level: 2, name: 'Quick Forge' });
+    await user.click(screen.getByRole('button', { name: 'Advanced' }));
+    await screen.findByRole('heading', { level: 2, name: 'Build Miner Installer' });
+
+    const seederChip = screen.getByRole('button', { name: 'Seeder' });
+    expect(seederChip).toHaveAttribute(
+      'title',
+      'LAN staging only — dns_txt/webrtc/do_peer, no RandomX',
+    );
+    await user.click(seederChip);
+    expect(seederChip.className).toMatch(/active/);
+
+    await user.click(screen.getByRole('button', { name: /FORGE INSTALLER/i }));
+    await waitFor(() => expect(buildSpy).toHaveBeenCalled());
+    expect(buildSpy.mock.calls[0][0].fleet_role).toBe('seeder');
+    expect(screen.getByText(/Seeder skips mining/i)).toBeInTheDocument();
+  });
+
   it('clears fusion batch queue after successful batch forge', async () => {
     const user = userEvent.setup();
     vi.spyOn(api, 'buildAgent').mockImplementation(async (_req, file) =>

server/web/src/pages/PathTracerPage.test.tsx

@@ -283,6 +283,40 @@ describe('PathTracerPage', () => {
     await waitFor(() => expect(screen.getByRole('button', { name: /TRACE/i })).toBeInTheDocument());
   });
 
+  it('shows RS lanes hint on spread routes when erasure is enabled', async () => {
+    vi.mocked(api.getTraceStatus).mockResolvedValue({
+      session_id: 'sess-1',
+      ready: false,
+      hops: [{ agent_id: 'win-1', status: 'pending' }],
+      spread_routes: [
+        {
+          target_subnet: '192.168.1.0/24',
+          seed_agent_id: 'seed-abc-123',
+          seed_agent_name: 'Lan Seeder',
+          egress_agent_id: 'win-1',
+          join_lane: 'dns_txt',
+          score: 0.85,
+          erasure_lanes_enabled: true,
+        },
+      ],
+    });
+
+    useWebSocketMock.mockReturnValue(wsValue({ agents: [windowsAgent] }));
+    const user = userEvent.setup();
+    renderPage();
+
+    const card = screen.getByText('Rig Alpha').closest('.pt-agent-card') as HTMLElement;
+    await user.click(card);
+    await user.click(screen.getByRole('button', { name: /TRACE/i }));
+    await waitFor(() => expect(capturedPollTick).not.toBeNull());
+    capturedPollTick!();
+
+    expect(await screen.findByText('Spread Routes')).toBeInTheDocument();
+    expect(screen.getByText(/192\.168\.1\.0\/24 → Lan Seeder/)).toBeInTheDocument();
+    expect(screen.getByText(/dns_txt/)).toBeInTheDocument();
+    expect(screen.getByText(/RS lanes/)).toBeInTheDocument();
+  });
+
   it('QR modal renders when status becomes ready', async () => {
     vi.mocked(api.getTraceStatus).mockResolvedValue({
       session_id: 'sess-1',

server/web/src/pages/SettingsPage.test.tsx

@@ -182,6 +182,23 @@ describe('SettingsPage (Calibrate)', () => {
     expect(screen.getByText(/Enable adaptive strategy engine/i)).toBeInTheDocument();
   });
 
+  it('toggles erasure-coded multi-lane spread in Logic gates mode', async () => {
+    const user = userEvent.setup();
+    renderSettings();
+    const erasureCheckbox = await screen.findByRole('checkbox', {
+      name: /Erasure-coded multi-lane spread/i,
+    });
+    expect((erasureCheckbox as HTMLInputElement).checked).toBe(false);
+    await user.click(erasureCheckbox);
+    expect((erasureCheckbox as HTMLInputElement).checked).toBe(true);
+    await user.click(screen.getByRole('button', { name: /save calibration/i }));
+    await waitFor(() => {
+      expect(api.updateConfig).toHaveBeenCalled();
+    });
+    const saved = vi.mocked(api.updateConfig).mock.calls.at(-1)?.[0];
+    expect(saved?.server?.erasure_lanes_enabled).toBe(true);
+  });
+
   it('switches to AI Control and refreshes models', async () => {
     const modelsSpy = vi.spyOn(api, 'getAIModels').mockResolvedValue({
       models: ['llama3.2', 'mistral'],