## Why
`--worktree` previously supported only `codex exec` and `codex exec fork`. Interactive sessions need the same managed checkout support, with configuration and policy resolved for the destination before starting a turn.
## What changed
- Enable `codex --worktree` and `codex fork --worktree <session-id>` behind the `worktrees` feature, restricted to local sessions. Interactive forks require an explicit session selector.
- Resolve interactive and exec worktree forks from the session's latest saved working directory unless `--cd` is supplied. Keep relative `--add-dir` paths anchored to the invocation directory.
- Load interactive destination configuration before telemetry and login policy initialization, and bind checkout ownership before the first turn.
- Reject explicitly untrusted sources, including when destination cloud policy or refreshed configuration reveals distrust. Retain unbound interactive checkouts after startup failure and report manual recovery instructions.
## Testing
Add CLI integration and TUI tests for startup and named forks, destination instructions and configuration, ownership before the first request, trust enforcement, and retained-checkout recovery. Extend exec coverage for saved fork directories, explicit `--cd`, relative writable roots, and cloud policy rejection.
GitOrigin-RevId: 371583f7feca73b218a4ff188b2b85812c8439e6
## What changed
- Add the experimental `worktrees` feature and a shared `--worktree` flag for new and forked `codex exec` sessions.
- Create each enabled session in a managed Git worktree, use that checkout as the session working directory, and bind the checkout to the new thread.
- Share the configured worktree pool with Desktop while leaving automatic cleanup disabled for CLI allocations.
- Reject unsupported commands, remote execution, ignored user configuration, ephemeral sessions, and use without the feature enabled before allocating a worktree.
## Testing
- Cover flag placement and inheritance, supported and rejected command combinations, worktree allocation and thread ownership, configuration gating, and compatibility with existing worktree-backed sessions.
GitOrigin-RevId: 011ff4639b09e8992c50d7b823df23e71798670e
