Document rollout and rollback plan

[osvaldoandrade]

Write operational plan for refactor release.

Goal: Safe rollout with clear rollback path.

Content:

• Write docs/ROLLOUT.md:
  • Release version X: refactored internals, backward compat aliases
  • Bake time: 1 release cycle (e.g., 3 months)
  • Monitoring: watch for unexpected import errors, runtime issues
  • Release version X+1: remove deprecated aliases (breaking change)
  • Rollback: revert to version X-1 if critical issues
• Semver: version X is minor bump, X+1 is major bump

Acceptance criteria:

• Rollout plan documented
• Rollback procedure clear
• Timeline communicated to users

Part of: #656
Requires: Migration guide complete