Fix TypeScript type conflicts and update build process

- Add overrides for @types/express to resolve version conflicts
- Remove SDK build step from CI as we're now using published version
- Move mcp.png to src/static folder and update serving path
- Add copy-static script to build process

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

package.json

@@ -32,5 +32,9 @@
     "dotenv": "^16.4.7",
     "express": "^4.21.2",
     "raw-body": "^3.0.0"
+  },
+  "overrides": {
+    "@types/express": "^5.0.0",
+    "@types/express-serve-static-core": "^5.0.2"
   }
 }