feat(deploy): build + serve worker and admin as static nginx images

- per-app Dockerfiles (vite build → nginx) + SPA nginx.conf
- Gitea workflow pushes 3 images; frontends bake VITE_API_URL
- docker-compose.prod.yml (registry images, solelog_network) + .env.prod.example
- docker-compose.yml runs the full stack locally; add .dockerignore

apps/admin/src/auth/AuthContext.test.tsx

@@ -17,9 +17,9 @@ vi.mock('../api/me', () => ({
 const mockedSignIn = vi.mocked(apiSignIn);
 const mockedFetchMe = vi.mocked(fetchMe);
 
-// A tiny harness that exposes the auth context's state + signIn.
+// A tiny harness that exposes the auth context's state + signIn + signOut.
 function Harness() {
-  const { isAuthed, signIn } = useAuth();
+  const { isAuthed, signIn, signOut } = useAuth();
   return (
     <div>
       <span data-testid="authed">{String(isAuthed)}</span>
@@ -34,6 +34,9 @@ function Harness() {
       >
         go
       </button>
+      <button type="button" onClick={() => signOut()}>
+        uit
+      </button>
       <span id="err" />
     </div>
   );