Feat/core 0.1.0 integration

[code3743]

This pull request introduces the first stable release (0.1.0) of the package, updating the documentation, adding a comprehensive feature gallery, and expanding both the example app and README to cover new features. The main changes include support for advanced stroke and clipping options, scene persistence and export, and improved asset handling. The example app now demonstrates these features interactively, and assets are bundled for out-of-the-box demos.

Feature Additions and Enhancements:

• Added support for stroke cap, join, miter, and dash array to Layers.rectangle and Layers.path, using Flutter's native enums and parameters. [1] [2] [3] [4]
• Introduced clipBehavior to clip layers to their bounding box, mirroring Flutter's Container behavior. [1] [2] [3] [4]
• Added uniform scale and configurable alignment to all Layers factories for advanced transforms. [1] [2] [3]
• Implemented word-wrap for Layers.text with vertical centering, and documented its behavior. [1] [2]

Persistence and Export:

• Added AssetImageSource for lazy asset loading and compact serialization, with automatic decoding and integration into all widgets and Scene persistence. [1] [2] [3] [4]
• Documented and demonstrated Scene.toJson()/fromJson() for round-trip persistence, and Scenes.encode/Scenes.saveToFile for exporting scenes to files in multiple formats. [1] [2] [3] [4] [5]

Documentation and Example Improvements:

• Expanded the README with a new "Gallery" section and detailed feature documentation, including usage examples for all new features. [1] [2] [3] [4] [5]
• Updated the example app to a StatefulWidget, adding interactive demos for dashed strokes, clipping, persistence, and export, and wiring up asset loading. [1] [2] [3] [4] [5]
• Added asset image to the example app and included the assets/images/logo.png in the pubspec for demo purposes.

Project Maintenance:

• Updated .pubignore to exclude the /doc/ directory from published packages.
• Updated version constraints and changelog to reflect the new stable release and features. [1] [2]

These changes collectively make the package feature-complete for Flutter use cases, with robust documentation and interactive examples.