#749 Phase 0: MCP front-door + durable run_goal agent tool

Highway Agents Phase 0 (option B). Engine: tools.agent.run_goal + tools.agent.init_goal (durable one-turn-per-invocation ReAct loop) in enterprise/tools/agent.py; registered in registry.py; wrapper api/dsl_templates/agent_run_goal.py; model gemma4:31b-cloud. Separate MCP server (run_goal/get_status/approve over REST, hw_k1_ Bearer). Static-validated (py_compile + DSL build); runtime dogfood pending image rebuild + tool-calling ollama model. Re-filed from a stale ~/develop clone.