feat: add infrastructure for MCP Apps

### Description
Adds support for returning structured content from tools, which is used by MCP Apps to pass complex data to the host. Also updates the resource index.

### Scenarios Tested
- Verified build and file changes.

Author: joehan

src/mcp/resources/index.ts

@@ -13,6 +13,10 @@ import { ServerResource, ServerResourceTemplate } from "../resource";
 import { trackGA4 } from "../../track";
 import { crashlytics_issues } from "./guides/crashlytics_issues";
 import { crashlytics_reports } from "./guides/crashlytics_reports";
+import { login_ui } from "./login_ui";
+import { update_environment_ui } from "./update_environment_ui";
+import { deploy_ui } from "./deploy_ui";
+import { init_ui } from "./init_ui";
 
 export const resources = [
   app_id,
@@ -25,6 +29,10 @@ export const resources = [
   init_firestore_rules,
   init_auth,
   init_hosting,
+  login_ui,
+  update_environment_ui,
+  deploy_ui,
+  init_ui,
 ];
 
 export const resourceTemplates = [docs];

src/mcp/util.ts

@@ -41,7 +41,8 @@ export function toContent(
   const suffix = options?.contentSuffix || "";
   return {
     content: [{ type: "text", text: `${prefix}${text}${suffix}` }],
-  };
+    structuredContent: data,
+  } as any;
 }
 
 /**