Summary

• Add a "Worktree continuation = drive to PR" rule under Git Conventions in CLAUDE.md.
• Codifies that when continuing half-done work in an existing worktree, the workflow is commit → push → open or update PR rather than stopping at local commits.
• Notes the discard path (git checkout) for stale changes that aren't real work (e.g. stale Cargo.lock after rebase on an already-merged branch).

Test plan

• Docs-only change; git diff reviewed.