git_graph: Add built-in branch and commit actions to the context menu

[sergiooroman]

Objective

The Git Graph context menu currently only offers read-only entries (View Commit, Copy SHA / Ref Name / Tag) plus user-defined custom commands. Common Git operations — checking out a branch, merging it, creating a branch from a commit, deleting a branch, cherry-picking — require leaving the graph, even though the graph is the natural place to perform them (as in VS Code's Git Graph extension, Fork, or Sublime Merge).

Solution

Adds built-in actions to the Git Graph context menu, all running through the native git backend (no terminal round-trip), so they work in remote projects too and refresh Zed's Git state as usual.

Right-clicking a branch label:

• Check Out Branch — Repository::change_branch (which already creates a local tracking branch for remote refs); disabled for the checked-out branch.
• Merge into <current branch> / Squash Merge into <current branch> — new native merge operation (git merge --no-edit <ref> / git merge --squash <ref>); disabled when the clicked ref is the checked-out branch. A squash merge stages the changes so they can be reviewed and committed from the Git Panel.
• Create Branch from Here… / Create Tag… — opens a small modal asking for the name, then Repository::create_branch (creates and switches, matching the branch picker's behavior) or the new native create_tag. The tag modal has an optional message field: filled in creates an annotated tag, empty creates a lightweight tag.
• Delete Branch… — confirmation prompt, then Repository::delete_branch, reusing the branch picker's force-delete fallback for unmerged branches. Remote-ness is resolved from the live branch list rather than guessed from the ref string.

Right-clicking a commit row:

• Check Out Commit — new native checkout_commit operation (git checkout --detach <sha>).
• Create Branch from Here… / Create Tag… — same modal, based on the commit SHA.
• Cherry-Pick Commit — new native cherry_pick operation.
• Revert Commit — new native revert operation (git revert --no-edit <sha>).

Right-clicking a tag label: Check Out Tag (detached), Create Branch from Here…, and Delete Tag… (with confirmation).

Backend changes:

• GitRepository gains merge (with a squash flag), cherry_pick, revert, checkout_commit, create_tag, and delete_tag, implemented for RealGitRepository and FakeGitRepository.
• New GitMerge, GitCherryPick, GitRevert, GitCheckoutCommit, GitCreateTag, and GitDeleteTag proto messages (462–467), with GitStore handlers and collab forwarding, so the operations work in shared/remote projects like the existing branch operations.
• Repository (git_store) exposes the operations following the same send_job local/remote pattern as change_branch.

Failure cases (e.g. a merge or cherry-pick with conflicts) surface through the standard git error toast with View Log, and conflicts can then be resolved from the Git Panel as usual.

User-defined custom commands keep working and stay in their own section below the built-in entries. Docs: added a "Git Graph" section to docs/src/git.md.

Testing

• New real-git test test_merge_cherry_pick_revert_and_checkout_commit in crates/git exercising the new backend operations end to end, including squash merge staging, lightweight vs. annotated tag creation, and tag deletion.
• New gpui test test_checkout_commit_detaches_head in crates/git_ui covering the graph-level action against the fake backend.
• Existing git_ui test suite passes (cargo test -p git_ui --lib), clippy clean with --deny warnings on all touched crates.
• Exercised manually on macOS against a local build.

Self-Review Checklist:

• I've reviewed my own diff for quality, security, and reliability
• Unsafe blocks (if any) have justifying comments
• The content adheres to Zed's UI standards (UX/UI and icon guidelines)
• Tests cover the new/changed behavior
• Performance impact has been considered and is acceptable

Release Notes:

• Added checkout, merge, squash merge, cherry-pick, revert, and branch and tag management actions to the Git Graph context menu.

🤖 Generated with Claude Code

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