feat: Update usage limit modal for Pro users

[charlesvien]

Problem

Pro users hitting the daily cap saw the same "upgrade to Pro" pitch as Free users, treating a normal reset window like a paywall.

Changes

1. Branch modal title and copy on plan and bucket (daily vs monthly)
2. Drop the upgrade CTA for Pro users; show a single "Got it" button
3. Add "Get support" button on the left that opens mailto:charles@posthog.com (Pro only)
4. Pass bucket and resetAt from the threshold event through to the store
5. Read isPro from useSeat so the rate-limit fallback path also branches correctly

How did you test this?

Manually

Publish to changelog?

no

[charlesvien]

• chore: Add config with AGENTS.md context and opt-out label for greptile #2400
• feat: Update usage limit modal for Pro users #2399 👈 (View in Graphite)
• docs: Deep links docs update #2398
• main

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[greptile-apps]

T-Rex Logs

What T-Rex did

• Rendered the UsageLimitModal in Pro and Free states via component tests.
• Tested burst and sustained usage, fallback show with invalid resetAt, and plan changes while the modal was open.
• Exercised the See Pro, Not now, Get support, and Got it button flows.
• Ran the existing usage limit store and reset-time utility tests for regression coverage.
• All focused tests and checks reported passing.

Artifacts

Generated UsageLimitModal component test run

• Evidence of the component test execution for the UsageLimitModal.

Generated UsageLimitModal component tests

• Source code for the UsageLimitModal tests used in this PR.

Existing usageLimitStore and billing utils test run

• Evidence of the regression tests for the usage limit store and billing utilities.

_{Ran code and verified through T-Rex}

Prompt To Fix All With AI

Fix the following 3 code review issues. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 3
apps/code/src/renderer/features/billing/subscriptions.ts:23-26
**Use event plan**

This threshold event already carries the authoritative `isPro` value from the usage monitor, but this path drops it and leaves the modal to recompute plan state from `useSeat()`. On app startup or after auth changes, the billing subscription can receive a 100% event while the seat fetch is still in flight, so a Pro user can be treated as Free and shown the `See Pro` upgrade CTA. Store the event's plan value with the modal context and use `useSeat()` only for fallback opens that do not come from a threshold event.

### Issue 2 of 3
apps/code/src/renderer/features/billing/components/UsageLimitModal.tsx:38-40
**Handle support failure**

`openExternal.mutate` returns a Promise, but this click handler drops it without `await`, `void`, or `.catch`. If the main process rejects the request or the mail client cannot be opened, the renderer gets an unhandled rejection and the user gets no feedback from the modal.

```suggestion
  const handleSupport = () => {
    void trpcClient.os.openExternal.mutate({ url: SUPPORT_MAILTO });
  };
```

### Issue 3 of 3
apps/code/src/renderer/features/billing/components/UsageLimitModal.tsx:61-63
**Preserve monthly copy**

For Free users on the sustained bucket, the title says they are out of usage for this month, but the body falls through to the generic `Free usage limit` wording. That loses the new bucket-specific message for the monthly cap and makes the modal copy disagree with itself.

```suggestion
    : `You've hit your Free ${
        isDaily ? "daily" : isMonthly ? "monthly" : "usage"
      } limit. Upgrade to Pro for 20x more usage.`;
```

_{Reviews (1): Last reviewed commit: "Update usage limit modal for Pro users" | Re-trigger Greptile}

[adboio]

this would probably be a good place to use the conversations product so we can set up automations (like message -> slack or something)

not blocking but something to consider moving fwd!

[charlesvien]

Merge activity

• May 28, 1:10 AM UTC: A user started a stack merge that includes this pull request via Graphite.
• May 28, 1:12 AM UTC: Graphite rebased this pull request as part of a merge.
• May 28, 1:17 AM UTC: @charlesvien merged this pull request with Graphite.