fix: decode run_tool subprocess output as UTF-8 to handle tqdm Unicode chars on Windows

gui/app.py

@@ -227,11 +227,14 @@ class ArmaModManagerApp(ctk.CTk):
             try:
                 env = os.environ.copy()
                 env["PYTHONUNBUFFERED"] = "1"
+                env["PYTHONUTF8"] = "1"
                 proc = subprocess.Popen(
                     [sys.executable, "-u", str(PROJECT_ROOT / script)] + extra,
                     stdout=subprocess.PIPE,
                     stderr=subprocess.STDOUT,
                     text=True,
+                    encoding="utf-8",
+                    errors="replace",
                     cwd=str(PROJECT_ROOT),
                     env=env,
                 )