fix(inbox): reconcile merged/closed PR state in the Pull requests tab

[posthog]

Problem

A merged PostHog Code pull request stayed listed as reviewable in the Inbox. The report kept its primary yellow Review button in the Pull requests tab and offered a Continue PR action that claimed an open PR already existed — directly conflicting with the merged/branch-deleted state on GitHub. Users couldn't tell an already-shipped report from active work, and could try to continue a PR that had already merged.

Root cause: tab membership and the PR action affordances trust the cloud report status, which lags GitHub. It stays ready until the backend reconciles a merge/close, so a merged report never dropped out of the actionable state on the client.

Changes

The app already fetches live GitHub PR state — the diff-stats batch on the list and getPrDetailsByUrl on the detail — but only used it to render the merged/closed badge. This reuses that same state for the action affordances:

• PullRequestCard de-emphasises the CTA to a neutral outline View button once the linked PR is merged/closed, so a shipped report reads differently from active work (alongside the existing violet "Merged" badge).
• ReportDetailActions drops the "Continue existing PR" path — and its "an open pull request already exists" copy — when the linked PR is no longer open, so users are never invited to continue a merged PR.
• The decision lives in a pure, unit-tested isImplementationPrClosedOrMerged helper in @posthog/core so both surfaces stay aligned. It handles both data shapes (GraphQL batch state: "merged" and the REST endpoint's state: "closed", merged: true).

No extra network cost: the detail hook reuses the getPrDetailsByUrl query the header PR badge already primes, and the card reads from the existing list batch.

How did you test this?

• pnpm --filter @posthog/core vitest on reportActions.test.ts — added 10 cases covering the new helper (open/draft/merged/closed across both data shapes); all 29 pass.
• Full core inbox suite (src/inbox): 168 pass.
• pnpm --filter @posthog/core --filter @posthog/ui typecheck — clean.
• biome lint on the changed files and packages/core (no noRestrictedImports) — clean.

Not verified in the running app: reproducing the live symptom needs a desktop Electron session with a real inbox report whose PR has merged but whose cloud status hasn't reconciled, which isn't reproducible in this environment. The behavioural change is gated purely on the already-fetched live PR state, and the pure reconciliation logic is unit-tested.

Automatic notifications

• Publish to changelog?
• Alert Sales and Marketing teams?

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Created with PostHog Code from an inbox report.

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[github-actions]

React Doctor found no issues in the changed files. 🎉

_{Reviewed by React Doctor for commit 2ad3c4c.}