[Bug]: Bitbucket merge still fails — removed /user/permissions/repositories endpoint returns 404, not 410

Summary

Merging a Bitbucket Cloud pull request from T3 Code fails with Bitbucket returned HTTP 404. The failure comes from the viewer-permission gate, not the merge call: GET /2.0/user/permissions/repositories was removed by Bitbucket (CHANGE-2770), and production Bitbucket answers 404 for it — but the fallback added in #6525 only recognises 410, so the removed-endpoint path never triggers and every write action is blocked.

Version

• T3 Code 0.0.34-nightly.20260824.1179 (trace below) and 0.0.35-nightly.20260826.1195; main still has the same check at apps/server/src/pullRequest/BitbucketPullRequestApi.ts:118.
• Linux (NixOS), AppImage build.
• Bitbucket Cloud, user API token. GET /2.0/user and all PR listing calls succeed with the same credential.

Trace

From ~/.t3/userdata/logs/server.trace.ndjson:

ws.rpc.pullRequests.runAction -> Failure
PullRequestOperationError: Pull request operation runAction failed: Bitbucket returned HTTP 404.
  [cause]: PullRequestProviderError: bitbucket failed in getViewerPermissions: Bitbucket returned HTTP 404.
    [cause]: BitbucketResponseError: Bitbucket API failed in request: Bitbucket returned HTTP 404.

The failing HTTP span:

GET https://api.bitbucket.org/2.0/user/permissions/repositories?q=repository.full_name%3D%22<workspace>%2F<repo>%22
http.response.status_code: 404

Confirming the endpoint is gone (not a permission problem)

Unauthenticated probes, so no token is involved:

$ curl -s -o /dev/null -w '%{http_code}\n' https://api.bitbucket.org/2.0/user
401
$ curl -s -o /dev/null -w '%{http_code}\n' 'https://api.bitbucket.org/2.0/user/permissions/repositories?q=repository.full_name%3D%22x%2Fy%22'
404
$ curl -s -o /dev/null -w '%{http_code}\n' https://api.bitbucket.org/2.0/user/permissions/workspaces
404

An existing endpoint answers 401 without auth; the removed ones answer 404 regardless of auth.

Cause

#6525 (closes #6341) added:

function isRepositoryPermissionRemovedError(error) {
  return error._tag === "BitbucketResponseError" && error.status === 410;
}

The PR notes it was not exercised against a live Bitbucket account and was coded to the documented 410. Real Bitbucket returns 404, so getRepositoryPermission still hard-fails, getViewerPermissions fails, and PullRequestService.viewerPermissionsOf blocks merge (and other writes) before the merge request is sent.

Suggested fix

Treat 404 from /2.0/user/permissions/repositories the same as 410 in isRepositoryPermissionRemovedError (permission unknown → not blocking), and update the unit test to cover both statuses. Happy to send a PR.

Start in apps/server/src/pullRequest/BitbucketPullRequestApi.ts at the permission check around line 118, then find its existing unit test. Reproduce the removed-endpoint handling for both HTTP 404 and 410, and run the relevant Bitbucket permission tests to confirm that viewer-permission lookup no longer blocks pull request actions.