fix(web): #295 align MachineKey wire field to server ({ apiKey }, not { key })

The server returns MachineKeyResponse(string ApiKey) -> JSON { apiKey }, but the
hand-written SPA MachineKey type declared { key } and ApiKeyScreen read result.key,
which would be undefined at runtime (blank key + empty copy). Mocked unit tests
passed against the wrong shape. Align the type, the screen, and both test mocks to
the real { apiKey } contract.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web/src/api/auth.test.ts

@@ -127,11 +127,11 @@ describe('auth endpoints', () => {
   });
 
   it('GET /api/auth/machine-key', async () => {
-    const fetchMock = vi.spyOn(window, 'fetch').mockResolvedValue(jsonResponse({ key: 'abc123' }));
+    const fetchMock = vi.spyOn(window, 'fetch').mockResolvedValue(jsonResponse({ apiKey: 'abc123' }));
 
     const result = await getMachineKey();
 
-    expect(result).toEqual({ key: 'abc123' });
+    expect(result).toEqual({ apiKey: 'abc123' });
     expect(fetchMock).toHaveBeenCalledWith('/api/auth/machine-key', expect.objectContaining({ method: 'GET' }));
   });
 });

web/src/api/auth.ts

@@ -21,9 +21,12 @@ export interface AuthSession {
   method: string | null;
 }
 
-/** `GET /api/auth/machine-key` — the server-generated machine API key (consumed by another slice). */
+/**
+ * `GET /api/auth/machine-key` — the server-generated machine API key.
+ * The wire field is `apiKey` (server record `MachineKeyResponse(string ApiKey)`), not `key`.
+ */
 export interface MachineKey {
-  key: string;
+  apiKey: string;
 }
 
 const legacyApiKeyStorageKey = 'ctv-api-key';

web/src/screens/ApiKeyScreen.test.tsx

@@ -16,7 +16,7 @@ function installFetch(options: { machineKey?: string; passwordStatus?: number }
   return vi.spyOn(window, 'fetch').mockImplementation((input: RequestInfo | URL) => {
     const url = typeof input === 'string' ? input : input instanceof URL ? input.toString() : input.url;
     if (url === '/api/auth/machine-key') {
-      return Promise.resolve(json({ key: machineKey }));
+      return Promise.resolve(json({ apiKey: machineKey }));
     }
     if (url === '/api/auth/password') {
       if (passwordStatus >= 400) {

web/src/screens/ApiKeyScreen.tsx

@@ -67,7 +67,7 @@ function MachineKeyCard() {
         if (!activeRef.current || seq !== seqRef.current) {
           return;
         }
-        setState({ status: 'success', key: result.key });
+        setState({ status: 'success', key: result.apiKey });
       })
       .catch((error: unknown) => {
         if (!activeRef.current || seq !== seqRef.current) {