v1.2.0

Added

• MigrationRunner::migrate(bool $dryRun = false) — pass dryRun: true to
  find out which migrations would be applied without running them. In
  dry-run mode up() is never called, no rows are written to the tracking
  table, and the tracking table isn't even created if it doesn't already
  exist. Returns the same string[] shape as a real run, so callers get a
  symmetrical preview/confirm API.
• README "Dry-Run Mode" section with a runnable example, plus an expanded
  Usage section covering a full deploy-script example.
• New test coverage proving a dry run leaves the target tables and the
  tracking table completely untouched, and that a subsequent real
  migrate() call applies everything normally.

See CHANGELOG.md for details.