Future: Formal \squad migrate\ command (informed by PR #199) #231

Context:
PR #199 by @williamhallatt proposed a comprehensive \squad migrate\ command for v0.5.x → v0.8.x migrations. The PR was closed as feedback for a future release, but it contains valuable patterns worth capturing.

Key Patterns from PR #199 to revisit:

• --dry-run flag — migration preview without side effects
• --backup-dir flag — safety checkpoint before migration
• --restore flag — rollback capability
• 57-test suite — reference model for migration test coverage (backup/restore validation, error handling, edge cases)
• cli-entry.ts regressions (4 fixes found during PR review):
  • Bare semver output (version number without 'squad v' wrapper)
  • Whitespace arg handling
  • Doctor hint display
  • NODE_NO_WARNINGS env var handling

Current Migration Infrastructure (as of v0.8.21-preview.3):

• migrate-directory.ts: 82 lines, handles .ai-team → .squad rename
• migrations.ts: 94 lines, version-based additive runner
• --migrate-directory flag on upgrade command

Next Steps:

1. Decide on formal \squad migrate\ CLI command signature
2. Reference PR fix(migrate): automated migration experience for v0.5.4 → v0.8.x #199's test patterns for migration safety validation
3. Fix the 4 cli-entry.ts regressions independently
4. Plan migration UX for v1.0 release window

Related: Closes after PR #199 (closed as feedback)