fix(gui_2): use str sentinel not bytes in _capture_workspace_profile

_repro.py

@@ -0,0 +1,29 @@
+"""Minimal reproducer for the auto_switch_sim GUI crash."""
+import sys
+import time
+import os
+sys.path.insert(0, 'C:/projects/manual_slop')
+sys.path.insert(0, 'C:/projects/manual_slop/src')
+
+from src.api_hook_client import ApiHookClient
+client = ApiHookClient()
+if not client.wait_for_server(timeout=15):
+    print('FAIL: server not up')
+    sys.exit(1)
+print('OK: server up')
+
+print('Step 1: click btn_reset')
+client.click('btn_reset')
+time.sleep(1.0)
+print('Step 1 done, status=', client.get_value('ai_status'))
+
+print('Step 2: set_value current_provider gemini_cli')
+client.set_value('current_provider', 'gemini_cli')
+time.sleep(1.0)
+print('Step 2 done')
+
+print('Step 3: set_value gcli_path')
+mock_path = os.path.abspath('tests/mock_concurrent_mma.py')
+client.set_value('gcli_path', '"' + sys.executable + '" "' + mock_path + '"')
+time.sleep(1.0)
+print('Step 3 done')