fix(oauth): treat Kiro social poll status as alias of error for pending states (#10620)

Kiro's device poll endpoint reports progress in a `status` field (e.g.
`authorization_pending`), but `classifyKiroSocialPoll()` only inspected
`data.error`. This caused every pre-authorization poll to fall through to
the terminal `invalid_token_response` error, making social login impossible
for Kiro AI and Amazon Q via Google/GitHub.

Changes:
- Add `status` field to `KiroSocialPollData` type
- Update `classifyKiroSocialPoll()` to check `data.status` as fallback
  for `data.error` when detecting pending states
- Add tests covering `status`-based pending detection and precedence

Closes #10618

src/lib/oauth/kiroSocialPoll.ts

@@ -1,5 +1,7 @@
 export type KiroSocialPollData = {
   error?: unknown;
+  /** Kiro reports poll progress here (e.g. "authorization_pending"), not in `error`. */
+  status?: unknown;
   accessToken?: unknown;
   refreshToken?: unknown;
 };
@@ -26,8 +28,9 @@ export function classifyKiroSocialPoll(
   responseStatus: number,
   data: KiroSocialPollData
 ): KiroSocialPollOutcome {
-  if (data.error === "authorization_pending" || data.error === "slow_down") {
-    return { kind: "pending", error: data.error };
+  const progress = data.error ?? data.status;
+  if (progress === "authorization_pending" || progress === "slow_down") {
+    return { kind: "pending", error: progress as "authorization_pending" | "slow_down" };
   }
 
   if (!responseOk || data.error) {