release: rename package @a2a/mcp → @a2amcp/mcp, bump to 0.1.1

The @a2a scope on npm is owned by a different account, so PUT against
the registry 404'd. Move to @a2amcp/mcp (scope we control) and bump the
version so the publish workflow has a fresh tag to push.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/cli.ts

@@ -229,7 +229,7 @@ program
       mcpServers: {
         a2a: {
           command: "npx",
-          args: ["-y", "@a2a/mcp"],
+          args: ["-y", "@a2amcp/mcp"],
         },
       },
     };