refactor: consolidate per-test subdirectories into flat test/api structure with merged returns and value files

test/api/value.c

@@ -0,0 +1,24 @@
+#include <string.h>
+
+#include "value.h"
+
+static WrenValue* value;
+
+static void setValue(WrenVM* vm)
+{
+  value = wrenGetArgumentValue(vm, 1);
+}
+
+static void getValue(WrenVM* vm)
+{
+  wrenReturnValue(vm, value);
+  wrenReleaseValue(vm, value);
+}
+
+WrenForeignMethodFn valueBindForeign(const char* signature)
+{
+  if (strcmp(signature, "static Api.value=(_)") == 0) return setValue;
+  if (strcmp(signature, "static Api.value") == 0) return getValue;
+
+  return NULL;
+}