New playbook that wraps the export and configure roles into a safe
IaC pipeline:
1. BACKUP - exports current live state to timestamped backups/ dir
2. PREVIEW - shows read-only diff of what config changes would do
3. APPLY - applies changes (gated behind -e apply=true)
Safety features:
- Preview-only by default (no changes without explicit opt-in)
- Automatic backup before any apply (relative to config_dir, not
playbook_dir, so backups don't land inside the collection tree)
- Strict mode opt-in via -e use_strict=true
- Preview step skippable with -e preview=false to halve API calls
- Rollback by re-applying from a backup directory
- Input validation for required variables
Updated README Quick Start to recommend the safe workflow, and added
api_url clarification note.