The compiler no longer auto-generates a default `new()` constructor for classes. All classes must now explicitly define `construct new() {}` to be instantiable. This change removes the `createDefaultConstructor` function from the compiler, eliminates the `return_this` primitive used by Object's default initializer, and adds explicit constructors to all test and example classes. Core metaclasses (Bool, Class, Null, Num, Object, Range, Sequence) now correctly reject `new()` calls with runtime errors.
Add two new Wren source files under example/import-module/ showing how to import and use a module. The cthulu.wren file defines a Cthulu class with a message method returning a Lovecraftian phrase, while lovecraft.wren imports the Cthulu class, instantiates it, and prints the message via IO.print.
