feat: add logical import support with wren_modules directory resolution and path type classification

Introduce a path type classification system (absolute, relative, simple) to distinguish logical imports from relative ones. Implement automatic discovery of a "wren_modules" directory by walking up from the root directory. Refactor the CLI to return interpret results and exit codes instead of exiting directly. Extract cross-platform stat macros into a shared header. Update test API calls to use explicit relative paths.

test/api/call.c

@@ -6,7 +6,7 @@
 void callRunTests(WrenVM* vm)
 {
   wrenEnsureSlots(vm, 1);
-  wrenGetVariable(vm, "test/api/call", "Call", 0);
+  wrenGetVariable(vm, "./test/api/call", "Call", 0);
   WrenHandle* callClass = wrenGetSlotHandle(vm, 0);
   
   WrenHandle* noParams = wrenMakeCallHandle(vm, "noParams");

test/api/get_variable.c

@@ -4,23 +4,23 @@
 
 static void beforeDefined(WrenVM* vm)
 {
-  wrenGetVariable(vm, "test/api/get_variable", "A", 0);
+  wrenGetVariable(vm, "./test/api/get_variable", "A", 0);
 }
 
 static void afterDefined(WrenVM* vm)
 {
-  wrenGetVariable(vm, "test/api/get_variable", "A", 0);
+  wrenGetVariable(vm, "./test/api/get_variable", "A", 0);
 }
 
 static void afterAssigned(WrenVM* vm)
 {
-  wrenGetVariable(vm, "test/api/get_variable", "A", 0);
+  wrenGetVariable(vm, "./test/api/get_variable", "A", 0);
 }
 
 static void otherSlot(WrenVM* vm)
 {
   wrenEnsureSlots(vm, 3);
-  wrenGetVariable(vm, "test/api/get_variable", "B", 2);
+  wrenGetVariable(vm, "./test/api/get_variable", "B", 2);
   
   // Move it into return position.
   const char* string = wrenGetSlotString(vm, 2);
@@ -29,7 +29,7 @@ static void otherSlot(WrenVM* vm)
 
 static void otherModule(WrenVM* vm)
 {
-  wrenGetVariable(vm, "test/api/get_variable_module", "Variable", 0);
+  wrenGetVariable(vm, "./test/api/get_variable_module", "Variable", 0);
 }
 
 WrenForeignMethodFn getVariableBindMethod(const char* signature)

test/api/main.c

@@ -25,7 +25,7 @@ static WrenForeignMethodFn bindForeignMethod(
     WrenVM* vm, const char* module, const char* className,
     bool isStatic, const char* signature)
 {
-  if (strncmp(module, "test/", 5) != 0) return NULL;
+  if (strncmp(module, "./test/", 7) != 0) return NULL;
 
   // For convenience, concatenate all of the method qualifiers into a single
   // signature string.
@@ -78,7 +78,7 @@ static WrenForeignClassMethods bindForeignClass(
     WrenVM* vm, const char* module, const char* className)
 {
   WrenForeignClassMethods methods = { NULL, NULL };
-  if (strncmp(module, "test/", 5) != 0) return methods;
+  if (strncmp(module, "./test/", 7) != 0) return methods;
 
   foreignClassBindClass(className, &methods);
   if (methods.allocate != NULL) return methods;

test/api/reset_stack_after_call_abort.c

@@ -6,7 +6,7 @@
 void resetStackAfterCallAbortRunTests(WrenVM* vm)
 {
   wrenEnsureSlots(vm, 1);
-  wrenGetVariable(vm, "test/api/reset_stack_after_call_abort", "Test", 0);
+  wrenGetVariable(vm, "./test/api/reset_stack_after_call_abort", "Test", 0);
   WrenHandle* testClass = wrenGetSlotHandle(vm, 0);
   
   WrenHandle* abortFiber = wrenMakeCallHandle(vm, "abortFiber()");

test/api/reset_stack_after_foreign_construct.c

@@ -22,7 +22,8 @@ void resetStackAfterForeignConstructBindClass(
 void resetStackAfterForeignConstructRunTests(WrenVM* vm)
 {
   wrenEnsureSlots(vm, 1);
-  wrenGetVariable(vm, "test/api/reset_stack_after_foreign_construct", "Test", 0);
+  wrenGetVariable(vm,
+      "./test/api/reset_stack_after_foreign_construct", "Test", 0);
   WrenHandle* testClass = wrenGetSlotHandle(vm, 0);
   
   WrenHandle* callConstruct = wrenMakeCallHandle(vm, "callConstruct()");