feat: implement List instantiation via "new" and fix inline functions to static

Add `list_instantiate` native to create empty lists, bind it to List's metaclass for `new` support, and remove the related TODO. Also change three `inline` functions in `wren_value.h` to `static inline` to prevent linker errors. Include a new test `test/list/new.wren` verifying `new List` yields an empty list that supports `add`.

test/list/new.wren

@@ -0,0 +1,6 @@
+var list = new List
+
+IO.print(list.count) // expect: 0
+IO.print(list) // expect: []
+list.add(1)
+IO.print(list) // expect: [1]