fix(portal-shell): send withCredentials on /me so the session cookie crosses SPA→BFF in dev

manual smoke surfaced the bug: the callback wrote the session and
set the portal_session cookie correctly, but the spa's next /me call
came back 401 with no cookie header at all.

root cause: angular's HttpClient via withFetch() inherits fetch's
default `credentials: 'same-origin'`. localhost:4200 → localhost:3000
is cross-origin (different ports), so the session cookie is dropped
on the way out — the bff never sees it. samesite=lax was a red
herring: localhost:4200 and localhost:3000 share the registrable
domain, so the cookie is still same-site; what was missing was
opting the fetch into credentials.

fix is per-call: only /me needs cookies today. login/logout are
full-page navigations through window.location, which the browser
hydrates with cookies regardless. a global HttpInterceptor will land
when other authenticated bff endpoints exist — premature for one
consumer.

bff side was already wired: enableCors({ credentials: true }) in
main.ts. nothing to change there.

a spec pins withCredentials=true on the /me request so a future
refactor can't silently drop the flag and reintroduce the bug.

libs/feature/auth/src/lib/auth.service.ts

@@ -58,7 +58,18 @@ export class AuthService {
    */
   async refresh(): Promise<void> {
     try {
-      const user = await firstValueFrom(this.http.get<CurrentUser>(this.meUrl));
+      // `withCredentials: true` is mandatory: the SPA at
+      // http://localhost:4200 calls the BFF at http://localhost:3000 —
+      // different origins, so `fetch`'s default `credentials:
+      // 'same-origin'` would drop the `__Host-portal_session` cookie
+      // and /me would always answer 401. Production (single origin
+      // behind the same edge) doesn't need it but it's harmless there.
+      // CORS on the BFF side already allows credentials
+      // (`apps/portal-bff/src/main.ts` → `enableCors({ credentials:
+      // true })`).
+      const user = await firstValueFrom(
+        this.http.get<CurrentUser>(this.meUrl, { withCredentials: true }),
+      );
       this._state.set({ kind: 'authenticated', user });
     } catch (err) {
       this._state.set(toErrorState(err));