BREAKING changes to the core:
- treeIterator is now a read-only `val`; added `iterator(order)` and use `asSequence(order)`.
- removeChild() only removes a direct child of the receiver; added `detach()` to unhook a node.
- addChild() rejects re-parenting and cycles (throws TreeNodeException); detach() first to move.
- clear() no longer nulls the receiver's own parent; only removes descendants.
- path() returns List<TreeNode<T>>? (null) instead of throwing.
Also:
- Enable strict explicitApi() across core + both modules; add explicit `public` modifiers.
- Update tests for the new contracts + add TreeNodeV4Test; refresh .api baselines.
- README + CHANGELOG (with migration notes); bump version to 4.0.0.
47 JVM tests green.
- Commit binary-compatibility-validator .api baselines for core + both modules.
- Replace JVM-only CI with a matrix: Ubuntu runs JVM/JS(node)/Wasm(node)/Native
+ apiCheck; macOS runs the iOS simulator tests.
- README: install + usage for tree-structure-serialization and -coroutines.
- Update kotlin-js-store/yarn.lock for the new modules' JS test deps.
Verified locally: JVM, JS(node), Wasm(node) and iOS-simulator tests pass for
core + both modules; native compiles & links (exec runs on the Linux CI runner).
