[Bug]: Branch name generation double-prefixes fix/ into feature/fix/

Before submitting

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

Area

packages/contracts or packages/shared

Steps to reproduce

1. Make a change that reads as a bug fix, or use a repo that follows Conventional Commits.
2. Create a PR from the default branch via "Commit, push & create PR" or "Create PR" with a feature branch.
3. Look at the branch name it created.

The branch naming prompt asks the model for "a short semantic git branch fragment". For a fix the model returns something like fix/calendar-recruitment-filter.

Expected behavior

The branch keeps its prefix and lands as fix/calendar-recruitment-filter, or feat/…, chore/…, and so on.

Actual behavior

It comes out as feature/fix/calendar-recruitment-filter. The feature/ prefix gets glued onto an already-prefixed fix/ fragment.

Cause

sanitizeFeatureBranchName in packages/shared/src/git.ts only treats a feature/ prefix as "already complete":

if (sanitized.includes("/")) {
  return sanitized.startsWith("feature/") ? sanitized : `feature/${sanitized}`;
}

Any other slash-separated fragment (fix/…, feat/…, chore/…) gets feature/ prepended. There is a test that currently codifies this as intended: CodexTextGeneration.test.ts expects feature/fix/important-system-change.

Impact

Minor bug or occasional failure

Version or commit

main

Environment

OpenCode provider, macOS

Workaround

Rename the branch after it is created, or create the branch and push it manually.

---

A small PR that fixes this is open at https://github.com/pingdotgg/t3code/pull/7074

Start with sanitizeFeatureBranchName in packages/shared/src/git.ts and the existing expectation in CodexTextGeneration.test.ts. Run that test to confirm the current behavior, then verify that conventional prefixes such as fix/, feat/, and chore/ remain intact without an extra feature/ prefix.