feat(billing) - facilitate top up in ai chat (#21645)

Today, when a trialing user hits their AI usage cap inside the Ask AI
chat, ending the trial bounces them to the Stripe billing portal (and,
for card-less users, loses their place in the conversation). This PR
makes activating a paid plan / topping up credits feel seamless from
within the chat:

Trial users with a card on file activate their subscription in place,
without leaving the app.
Trial users without a card are sent to the Stripe payment-method portal
and, on return, the trial is ended automatically and they're dropped
back into the exact Ask AI thread they came from.
Credit-exhaustion and trial banners now reflect whether a payment method
exists (Add Credit Card vs Subscribe Now / End Trial Period) and upgrade
inline via a confirmation modal instead of redirecting to Settings.


Uploading Screen Recording 2026-06-16 at 07.51.12.mov…


https://github.com/user-attachments/assets/4ea77273-da63-4b32-b6f1-5ac9e9560651



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packages/twenty-front/src/modules/ai/utils/buildAskAiThreadRedirectPath.ts

@@ -0,0 +1,22 @@
+import { ASK_AI_THREAD_ID_QUERY_PARAM } from '@/ai/constants/AskAiThreadIdQueryParam';
+import { isNonEmptyString } from '@sniptt/guards';
+
+export const buildAskAiThreadRedirectPath = ({
+  pathname,
+  search,
+  threadId,
+}: {
+  pathname: string;
+  search: string;
+  threadId: string | null;
+}): string => {
+  const searchParams = new URLSearchParams(search);
+
+  if (isNonEmptyString(threadId)) {
+    searchParams.set(ASK_AI_THREAD_ID_QUERY_PARAM, threadId);
+  }
+
+  const queryString = searchParams.toString();
+
+  return queryString.length > 0 ? `${pathname}?${queryString}` : pathname;
+};