* feat(blueprint): refactor BlueprintComponent as proper ECS Component
- Convert BlueprintComponent from interface to actual ECS Component class
- Add ready-to-use BlueprintSystem that extends EntitySystem
- Remove deprecated legacy APIs (createBlueprintSystem, etc.)
- Update all blueprint documentation (Chinese & English)
- Simplify user API: just add BlueprintSystem and BlueprintComponent
BREAKING CHANGE: BlueprintComponent is now a class extending Component,
not an interface. Use `new BlueprintComponent()` instead of
`createBlueprintComponentData()`.
* chore(blueprint): add changeset for ECS component refactor
* fix(node-editor): fix connections not rendering when node is collapsed
- getPinPosition now returns node header position when pin element is not found
- Added collapsedNodesKey to force re-render connections after collapse/expand
- Input pins connect to left side, output pins to right side of collapsed nodes
* chore(node-editor): add changeset for collapse connection fix
* feat(blueprint): add Add Component nodes for entity-component creation
- Add type-specific Add_ComponentName nodes via ComponentNodeGenerator
- Add generic ECS_AddComponent node for dynamic component creation
- Add ExecutionContext.getComponentClass() for component lookup
- Add registerComponentClass() helper for manual component registration
- Each Add node supports initial property values from @BlueprintProperty
* docs: update changeset with Add Component feature
* feat(blueprint): improve event nodes with Self output and auto-create BeginPlay
- Event Begin Play now outputs Self entity
- Event Tick now outputs Self entity + Delta Seconds
- Event End Play now outputs Self entity
- createEmptyBlueprint() now includes Event Begin Play by default
- Added menuPath to all event nodes for better organization