fix(@angular/cli): promote zoneless migration MCP tool to stable

The zoneless migration tool has been moved from the experimental to the stable toolset within the MCP server, making it available by default.

(cherry picked from commit ea4fb9d)

Author: clydin

packages/angular/cli/src/commands/mcp/mcp-server.ts

@@ -30,13 +30,14 @@ const STABLE_TOOLS = [
   DOC_SEARCH_TOOL,
   FIND_EXAMPLE_TOOL,
   LIST_PROJECTS_TOOL,
+  ZONELESS_MIGRATION_TOOL,
 ] as const;
 
 /**
  * The set of tools that are available but not enabled by default.
  * These tools are considered experimental and may have limitations.
  */
-export const EXPERIMENTAL_TOOLS = [MODERNIZE_TOOL, ZONELESS_MIGRATION_TOOL] as const;
+export const EXPERIMENTAL_TOOLS = [MODERNIZE_TOOL] as const;
 
 export async function createMcpServer(
   options: {