Rename skill to 'create-mcp-app' to align with spec

As per the spec (https://agentskills.io/specification) `name` should be:

 "Max 64 characters. *Lowercase letters*, numbers, and *hyphens* only. Must not start or end with a hyphen."

Author: vgshenoy

plugins/mcp-apps/skills/create-mcp-app/SKILL.md

@@ -1,5 +1,5 @@
 ---
-name: Create MCP App
+name: create-mcp-app
 description: This skill should be used when the user asks to "create an MCP App", "add a UI to an MCP tool", "build an interactive MCP View", "scaffold an MCP App", or needs guidance on MCP Apps SDK patterns, UI-resource registration, MCP App lifecycle, or host integration. Provides comprehensive guidance for building MCP Apps with interactive UIs.
 ---