[Bug]: "Commit, push & PR" can't find the open PR when the only remote isn't named origin, and fails on gh pr create #15373

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/server

Steps to reproduce

Single-repository workflow (no fork) where the only remote is not named origin:

1. Clone a repo and name its only remote something else: git clone --origin fork https://github.com/<owner>/<repo>.git (or git remote rename origin fork).
2. gh repo set-default <owner>/<repo> (the same repo fork points to).
3. On branch dev (tracking fork/dev), commit and push, then open a PR dev → main in <owner>/<repo>. The first "Commit, push & PR" run does this fine.
4. Commit again and run Commit, push & PR a second time while that PR is still open.

Expected behavior

The commit and push succeed, and the PR step finds the open PR and returns it (opened_existing), as it does when the remote is named origin.

Actual behavior

The commit and push succeed, but the action ends with:

Source control provider github failed in createChangeRequest: GitHub CLI command failed.

T3 Code calls gh pr create again, and gh refuses:

a pull request for branch "dev" into branch "main" already exists:
https://github.com/<owner>/<repo>/pull/3

Cause

Same root assumption as #7382 (the remote literally named origin is treated as the base repository), but a different failure: the existing-PR lookup rejects a same-repository PR.

In resolveBranchHeadContext (apps/server/src/git/GitManager.ts), resolveRemoteRepositoryContext(cwd, "origin") returns all nulls because there is no origin remote, so isCrossRepository falls through to the fallback branch:

const isCrossRepository =
  remoteRepository.repositoryNameWithOwner !== null && originRepository.repositoryNameWithOwner !== null
    ? /* compare */
    : remoteName !== null && remoteName !== "origin" && remoteRepository.repositoryNameWithOwner !== null;
//    ^ "fork" !== "origin" → true, although head and base are the same repository

findOpenPr then lists the PR correctly (gh pr list --head <owner>:dev / dev returns #3 with isCrossRepository: false), but matchesBranchHeadContext discards it:

if (headContext.isCrossRepository) {
  if (pr.isCrossRepository === false) return false;   // the real PR is dropped here
  ...
}

runPrStep concludes that no PR exists and goes on to createChangeRequest, which fails.

Renaming the remote to origin works around it: isCrossRepository becomes false, the selector is dev, and the PR matches.

Suggested fix

Don't infer the base repository from the remote name. Use what gh already resolved (gh repo set-default / remote.<name>.gh-resolved=base, or gh repo view --json nameWithOwner) as the target repository, and treat the head as cross-repository only when the head remote's nameWithOwner differs from it. The fallback remoteName !== "origin" heuristic produces a false positive whenever the only remote has a different name. This would also cover #7382.

Impact

Minor bug or occasional failure

Version or commit

0.0.45-nightly.20261002.2584

Environment

Linux (Fedora 44 / Bluefin), desktop AppImage, gh logged in via keyring