package:stem_flutter v0.3.0

• Documented core StemApp.runUntilIdle for app-owned background callbacks,
  including admission deadlines, safe draining, outcome mapping, and OS limits.
• Added StemFlutter.createApp, returning the ordinary core StemApp with
  Flutter initialization and local-worker defaults; re-exported the stable API.
• Required Stem >=0.4.1 <0.5.0 for bounded runs and lifecycle fixes.
• Breaking: Removed the Flutter queue monitor, snapshot/tracked-job models,
  custom worker host, and worker signal/status protocol. Use existing core Stem
  APIs instead.
• Removed TimeMachine initialization and its dependency from the adapter-neutral
  package. Required Ormed dependency setup now lives in stem_flutter_sqlite.
• Removed binary asset payload helpers for the custom worker-isolate protocol.
• Kept debug presentation in the example rather than the integration package.
• Replaced manual isolate setup with standard Stem task APIs.