v0.3.0

[0.3.0] - 2025-01-04

Effects, TaskManager, and Subscriptions for declarative async handling.

Added

• EffectStore - reducer returns effects alongside state changes
• EffectStoreWithMiddleware - effect store with middleware support
• DispatchResult<E> - result type with changed flag and effects vec
• TaskManager - spawn/cancel async tasks that produce actions
  • spawn(key, future) - run task, cancel previous with same key
  • debounce(key, duration, future) - debounced task execution
  • cancel(key) / cancel_all() - task cancellation
  • pause() / resume() - pause/resume task output
• Subscriptions - interval and stream-based action sources
  • interval(key, duration, action_fn) - periodic action emission
  • interval_immediate(key, duration, action_fn) - emit immediately then periodically
  • stream(key, stream, map_fn) - forward stream items as actions
  • cancel(key) / cancel_all() - subscription cancellation
  • pause() / resume() - pause/resume subscriptions
• DebugLayer::with_task_manager() - auto-pause tasks in debug mode
• DebugLayer::with_subscriptions() - auto-pause subscriptions in debug mode
• Weather example: multi-color sprite layers (sun=yellow, cloud=gray, etc.)
• Weather example: loading indicator in title bar (sprite stays visible during refresh)

Changed

• Weather example now uses EffectStore with TaskManager and Subscriptions