feat(mcp): add scenario tools and fix per-request server lifecycle
- add list_scenarios, get_scenario, create_scenario, update_scenario, delete_scenario
- add create_scenario_step, get_scenario_step, update_scenario_step, delete_scenario_step
- add list_scenario_runs, run_scenario
- import ScenarioModule into McpModule so ScenarioService is injectable
- move tool registration to private registerTools(server) method; create
fresh McpServer per request in handle() to satisfy SDK one-connection rule
- fix mcp.controller.spec: parse SSE data line instead of res.body; assert
exact status 200 everywhere; remove vague toBeLessThan(500) guards
ars9
d9cdb64ee2