group workspace fix

[paullizer]

• Group Workspace Documents and Prompts Load Recovery
  • Fixed a Group Workspace page-load regression where active-group initialization could fail on a missing prompt-role UI container and stop the rest of the page from rendering correctly.
  • Group document and prompt content now continue loading even if the prompt permission banner or create-button container is unavailable during startup, preventing blank content areas caused by a JavaScript null-reference error.
  • Added functional and UI regression coverage for the guarded prompt-role path so future changes do not reintroduce the same startup failure.
  • (Ref: group_workspaces.html, test_group_workspace_prompt_role_ui_guard.py, test_group_workspace_prompt_role_containers_ui.py)