Dry-run mode

[hsyntax]

Parent PRD

#1

What to build

Add a --dry-run CLI flag that lets the user validate the full pipeline without side effects.

Behavior:

• Runs the full loop including agent selection, worktree creation, implementation, and review
• Skips: git push, PR creation/submission, and marking the task as in-progress or done on the remote source
• Useful for validating the full pipeline without side effects
• Logs clearly indicate "[DRY RUN]" when skipping actions

Acceptance criteria

• --dry-run runs choose, implement, review but skips push/PR/state marking
• --dry-run logs clearly indicate skipped actions
• No remote side effects in dry-run mode (no labels changed, no PRs created)
• Integration tests: dry-run skips push/submit/mark operations
• cargo clippy and cargo fmt pass

Blocked by

• Blocked by Orchestrator + GitHub submission — first end-to-end loop #6 (orchestrator + single loop must work first)

User stories addressed

• User story 4 (dry-run)