When bd sync pushes from the sync-branch worktree, the pre-push hook
would detect uncommitted JSONL changes and suggest running bd sync -
which is circular since that's what the user is already doing.
Fix: Set BD_SYNC_IN_PROGRESS=1 environment variable when pushing from
worktree, and update pre-push hook to skip checks when this var is set.
Updated files:
- internal/syncbranch/worktree.go: Set env var on push command
- cmd/bd/templates/hooks/pre-push: Check for env var and exit early
- examples/git-hooks/pre-push: Same check
- .beads-hooks/pre-push: Same check