[karthik] fix: resolve debugger filepath-not-found on Linux

On Linux (case-sensitive FS), Directory.py lowercased child paths
before os.path.isfile(), so mixed-case files like Apps.py were never
indexed. Debugleton.py then lowercased the lookup too, guaranteeing
no match. Fix: store real paths always; on darwin only, lowercase
both sides at compare time. Closes #58.

debugger/debugger_backend/Directory.py

@@ -41,7 +41,7 @@ class Directory:
             ordered_abspaths.append({"abspath": full_path, "instance": dir})
             # print(f"\t[construct_ordered_abspaths]: Full path: {full_path}")
             for child in dir.children:
-                child_abspath = os.path.join(root_dir, child.path).lower()
+                child_abspath = os.path.join(root_dir, child.path)
                 if os.path.isdir(child_abspath):
                     construct_ordered_abspaths(child, ordered_abspaths)
                 elif os.path.isfile(child_abspath):