Fixes#1076.
When git worktrees have sparse-checkout enabled, git add operations can
fail with 'outside of sparse-checkout cone' errors. Adding the --sparse
flag allows git to stage files outside the sparse-checkout cone.
Changes:
- Add --sparse flag to git add in daemon_sync_branch.go (line 165)
- Add --sparse flag to git add in migrate_sync.go (line 343)
- Add --sparse flag to git add in sync_branch.go (line 308)
- Add --sparse flag to git add in worktree.go (line 732)
All changes include comments referencing #1076 for traceability.
6a4a6170e7