feat(worktrees): reflog-backed undo for worktree/branch deletion

[liam-russell]

Type

• feat — new feature or user-visible capability

Summary

• Deleting a worktree (and its branch, when applicable) now shows a toast with an Undo action that recreates the branch and re-adds the worktree at its original path.
• The undo window matches the toast's normal 5s auto-dismiss; letting it expire or dismissing it manually just lets the deletion stand as before.

Why

Worktree/branch deletion was previously guarded only by a confirm dialog, with no way to recover from a mistake short of manually replaying git reflog by hand. Closes #93.

Screenshots / recordings

Verified manually via the new E2E test — after removing a worktree, the "Worktree removed" success toast shows a green "Undo" button next to the copy/dismiss icons, and clicking it restores the worktree and its branch in the sidebar.

Breaking changes

None. WORKTREE_DELETE's IPC result changed from void to a WorktreeDeleteResult object ({ worktreePath, branch, branchSha }) so the renderer can drive Undo — additive change, no existing caller relied on the void return.

Test plan

• Added unit tests in packages/git/src/__tests__/worktrees.test.ts covering: SHA capture + full restore, restore when the branch was preserved (no SHA needed), and the two failure paths (no branch to restore; branch gone with no captured SHA).
• Added an E2E test in e2e/specs/worktree-workflow.spec.ts that creates a worktree, removes it via the context menu, clicks the toast's Undo button, and asserts the worktree/branch reappear in the sidebar.
• pnpm lint && pnpm typecheck && pnpm test all pass locally (unit + full E2E suite, 14 spec files).

[Copilot]

Pull request overview

Adds an undoable workflow for destructive worktree deletion by capturing branch state at delete-time (including branch SHA when the ref is deleted), exposing that via IPC to the renderer, and wiring a toast “Undo” action to restore the worktree/branch within the toast’s dismissal window.

Changes:

• Introduces WorktreeDeleteResult and updates worktree:delete IPC to return it; adds new worktree:restore IPC to reverse a deletion.
• Implements restoreDeletedWorktree in @sproutgit/git (recreate branch ref if needed, then git worktree add back at the original path).
• Adds unit + E2E coverage for delete-capture + restore and adds a toast action API to render an Undo button.

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
packages/ui/src/index.ts	Re-exports new toast action type.
packages/ui/src/components/Toast.tsx	Adds optional toast action rendering (Undo button).
packages/types/src/ipc.ts	Adds WORKTREE_RESTORE and updates IPC typing (worktree:delete result + worktree:restore).
packages/types/src/git.ts	Adds WorktreeDeleteResult type used across IPC and git layer.
packages/git/src/worktrees.ts	Returns delete undo state and implements restoreDeletedWorktree.
packages/git/src/index.ts	Exposes restoreDeletedWorktree from the git package entrypoint.
packages/git/src/tests/worktrees.test.ts	Unit tests for delete capture + restore success/failure paths.
e2e/specs/worktree-workflow.spec.ts	E2E test for toast Undo restoring worktree/branch in UI.
app/src/renderer/toast-context.tsx	Extends toast function signature to accept an optional action.
app/src/renderer/routes/workspace.tsx	Wires delete -> toast Undo -> restore mutation flow.
app/src/renderer/routes/__root.tsx	Stores toast actions in state so the UI can render Undo.
app/src/renderer/queries.ts	Updates delete mutation return type and adds restore mutation + query invalidation.
app/src/preload/index.ts	Exposes restoreWorktree and updates deleteWorktree return type in the preload API.
app/src/main/worktree-lifecycle.ts	Propagates delete undo state from git layer through the lifecycle function.
app/src/main/ipc/git.ts	Adds WORKTREE_RESTORE handler and returns delete result from WORKTREE_DELETE.