determineMappingStrategy
fun determineMappingStrategy(sourceField: FieldInfo, targetField: FieldInfo, isReverse: Boolean = false): MappingStrategy
Entry point per (sourceField, targetField) pair: runs field-level compile-time preconditions once, then resolves the strategy. Element-level recursion (collections, maps) bypasses the preconditions so they fire once per field, not per recursion step.