feat(scenarios): require environment for scenario runs

- require environmentId when creating runs in API and MCP tools

- pass selected environment data into step execution helpers

- prompt for environment selection before running scenarios in UI

server/src/mcp/mcp.service.ts

@@ -670,11 +670,15 @@ export class McpService {
         description: "Trigger an immediate run of a scenario by ID",
         inputSchema: {
           id: z.string().uuid().describe("Scenario ID to run"),
+          environmentId: z
+            .string()
+            .uuid()
+            .describe("Environment ID to run the scenario in"),
         },
       },
-      async ({ id }) => {
+      async ({ id, environmentId }) => {
         try {
-          const run = await this.scenarioService.createRun(id);
+          const run = await this.scenarioService.createRun(id, environmentId);
           return {
             content: [{ type: "text" as const, text: JSON.stringify(run) }],
           };