CLI: `but resolve finish` fails with config access error in edit mode

[sdrshn-nmbr]

Issue: but resolve finish fails with "No default target branch set" after resolving conflicts

Summary

When resolving conflicts in a stacked branch using but resolve, the but resolve finish command fails even after all conflict markers are resolved and files are staged.

Steps to Reproduce

1. Create/work on a stacked branch with multiple conflicted commits
2. Enter resolve mode: but resolve <commit-id>
3. Manually resolve all conflict markers in files
4. Stage resolved files: git add <files>
5. Verify all conflicts resolved: git status shows no unmerged files
6. Attempt to finish: but resolve finish

Expected Behavior

but resolve finish should complete the conflict resolution and commit the changes (as documented for UI "Save and Exit" behavior).

Actual Behavior

Error: Setup required: No default target branch set.

Environment

• GitButler Version: 0.19.1
• OS: macOS
• Git: Yes, repo has valid remote origin/dev

Proof of Configuration

$ cat .git/gitbutler/virtual_branches.toml | grep -A 6 '\[default_target\]'
[default_target]
branchName = "dev"
remoteName = "origin"
remoteUrl = "https://github.com/<example>"
sha = "f33f1c373023debd22a70022b3a5dac0b6e1a9d2"
pushRemoteName = "origin"

$ git rev-parse origin/dev
f33f1c373023debd22a70022b3a5dac0b6e1a9d2  # ✅ Valid and reachable

Root Cause Analysis

The CLI appears to fail reading the default target configuration from .git/gitbutler/virtual_branches.toml when in gitbutler/edit branch context. The configuration exists and is valid, but the but resolve finish command cannot access it.

Workaround

Use GitButler GUI to exit resolve mode: click "Save changes and exit" button instead of CLI.