perf(bind): speed up account bind detection and runtime sync

Replace the 1.8s polling interval with a 650ms tick plus a debounced
navigation-driven detect, listen for page-title-updated to catch SPA
transitions, and flush the session asynchronously. The bind handler
now optimistically seeds the runtime account list via
noteRuntimeAccountBound and fires the full server refresh in the
background, so the UI reflects the new binding without waiting on a
round-trip.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/desktop-client/src/main/runtime-controller.ts

@@ -1058,6 +1058,37 @@ export async function refreshRuntimeAccounts(): Promise<void> {
   await syncAccounts("manual");
 }
 
+export function noteRuntimeAccountBound(account: DesktopAccountInfo): void {
+  const normalizedAccount: DesktopAccountInfo = {
+    ...account,
+    platform_uid: normalizeAccountPlatformUid(account.platform_uid) || account.platform_uid,
+  };
+  const existingIndex = state.accounts.findIndex((item) =>
+    item.id === normalizedAccount.id
+    || (
+      item.platform === normalizedAccount.platform
+      && sameAccountPlatformUid(item.platform_uid, normalizedAccount.platform_uid)
+    ),
+  );
+
+  if (existingIndex >= 0) {
+    state.accounts = state.accounts.map((item, index) =>
+      index === existingIndex ? normalizedAccount : item,
+    );
+  } else {
+    state.accounts = [normalizedAccount, ...state.accounts];
+  }
+
+  state.accountProfiles.set(normalizedAccount.id, {
+    platformUid: normalizedAccount.platform_uid,
+    displayName: normalizedAccount.display_name,
+    avatarUrl: normalizedAccount.avatar_url,
+  });
+  state.lastAccountsSyncAt = Date.now();
+  syncTrackedAccounts(state.accounts.map((item) => accountIdentityFromDesktopAccount(item)));
+  refreshAccountNames();
+}
+
 export async function unbindRuntimeAccount(accountId: string, syncVersion: number): Promise<void> {
   const matchedAccount = state.accounts.find((item) => item.id === accountId) ?? null;