fix(@angular/cli): cache MCP best practices content and add tool annotations

Caches the content of the best practices instructions to avoid redundant file reads on subsequent uses of the tool. This can provide a minor performance improvement in cases where the tool is used multiple times during a single CLI process.

Also, annotations have been added to the text to provide additional context for the assistant and allow for more tailored display of the information.

(cherry picked from commit 51d56f7)

Author: clydin

packages/angular/cli/src/commands/mcp/tools/best-practices.ts

@@ -11,6 +11,8 @@ import { readFile } from 'node:fs/promises';
 import path from 'node:path';
 
 export function registerBestPracticesTool(server: McpServer): void {
+  let bestPracticesText;
+
   server.registerTool(
     'get_best_practices',
     {
@@ -27,7 +29,7 @@ export function registerBestPracticesTool(server: McpServer): void {
       },
     },
     async () => {
-      const text = await readFile(
+      bestPracticesText ??= await readFile(
         path.join(__dirname, '..', 'instructions', 'best-practices.md'),
         'utf-8',
       );
@@ -36,7 +38,11 @@ export function registerBestPracticesTool(server: McpServer): void {
         content: [
           {
             type: 'text',
-            text,
+            text: bestPracticesText,
+            annotations: {
+              audience: ['assistant'],
+              priority: 0.9,
+            },
           },
         ],
       };