Extract HTML DSL and VDOM into separate packages

[kevin-sakemaer]

Summary

This PR extracts the HTML DSL and Virtual DOM functionality from the spark framework package into two new standalone packages: spark_html_dsl and spark_vdom. This improves modularity, allows independent versioning, and enables use of these components outside the full Spark framework.

Key Changes

• New spark_html_dsl package: Contains core node types (Node, Text, RawHtml, Element) and HTML DSL helpers (h(), div(), span(), p(), a(), button(), input(), etc.)

  • Moved from packages/spark/lib/src/html/node.dart and elements.dart
  • Includes CSP nonce injection support via Dart Zones
  • Provides Element.eventWrapper static hook for event wrapping
  • Comprehensive test coverage in elements_test.dart, html_test.dart, and node_test.dart

• New spark_vdom package: Contains the browser-side Virtual DOM engine

  • Moved from packages/spark/lib/src/component/vdom_web.dart
  • Exports mount(), mountList(), patch(), and createNode() functions
  • Handles efficient DOM diffing, patching, and hydration
  • Includes SVG namespace handling and foreignObject context switching
  • Provides conditional exports: browser implementation for web, stub for VM/server
  • Comprehensive test coverage including memory leak tests, hydration tests, and attribute patching tests

• Updated spark package: Now depends on spark_html_dsl and spark_vdom as external dependencies

  • Removed internal HTML DSL and VDOM implementations
  • Updated all imports to use the new packages
  • Removed packages/spark/lib/src/html/dsl.dart and extensions.dart
  • Updated spark.dart to re-export from new packages

• Updated workspace: Added new packages to pubspec.yaml workspace configuration

• Test updates: Migrated all HTML DSL and VDOM tests to their respective new packages, with updated imports throughout the spark package test suite

Notable Implementation Details

• Both new packages use conditional imports to provide browser-specific implementations while maintaining VM/server compatibility
• The VDOM engine includes sophisticated namespace handling for SVG elements and proper context switching for foreignObject
• CSP nonce injection is implemented via Dart Zones, allowing secure inline script/style injection
• Event listener cleanup is properly handled to prevent memory leaks during DOM patching
• Hydration logic intelligently skips comment nodes and reuses existing DOM elements when possible

https://claude.ai/code/session_016djT9tGK3QkDpcRN7gmerd