fix(ext/popup): defensive Promise.allSettled in devices (Plan C Phase 5)

DEV-C P2: Promise.all meant one rejected RPC failed the whole render.
allSettled + per-slot fallback keeps the active-devices surface usable
when the revoked-list feed (or one bad ssh fingerprint) is down.

Two call sites converted in devices.ts:
  1. list_devices + list_revoked pair — revoked failures now render an
     inline "couldn't load" slot instead of failing the page.
  2. sshFingerprint map — one bad public key falls back to '(unknown)'
     instead of killing the whole device list.

trash.ts only has a single sendMessage in its load path on this branch,
so it has no Promise.all to migrate. Plan was written against a slightly
different snapshot; documented divergence in report.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

extension/src/popup/components/__tests__/devices.test.ts

@@ -95,6 +95,32 @@ describe('devices view', () => {
     expect(app.querySelector<HTMLButtonElement>('#register-confirm-btn')).not.toBeNull();
   });
 
+  // Plan C Phase 5 — defensive Promise.allSettled:
+  // a rejected secondary feed (list_revoked) should not kill the whole render.
+  it('renders devices when revoked list fails (load-error slot shown)', async () => {
+    (sendMessage as ReturnType<typeof vi.fn>)
+      .mockResolvedValueOnce({ ok: true, data: { devices: [{ name: 'CLI', public_key: 'k', added_at: 1 }] } })
+      .mockRejectedValueOnce(new Error('boom'));
+
+    await renderDevices(app);
+
+    // Primary list still rendered.
+    expect(app.innerHTML).toContain('CLI');
+    // Inline fallback slot present.
+    expect(app.innerHTML).toContain("Couldn't load revoked devices");
+  });
+
+  it('renders devices when revoked list returns {ok:false}', async () => {
+    (sendMessage as ReturnType<typeof vi.fn>)
+      .mockResolvedValueOnce({ ok: true, data: { devices: [{ name: 'CLI', public_key: 'k', added_at: 1 }] } })
+      .mockResolvedValueOnce({ ok: false, error: 'list_revoked_failed' });
+
+    await renderDevices(app);
+
+    expect(app.innerHTML).toContain('CLI');
+    expect(app.innerHTML).toContain("Couldn't load revoked devices");
+  });
+
   it('confirming register sends register_this_device with the entered name', async () => {
     (chrome.storage.local.get as ReturnType<typeof vi.fn>).mockResolvedValueOnce({ device_name: 'Unknown' });
     // Initial render: list_devices + list_revoked.