feat: add xxhash-wasm dependency for cch signing

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

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

package.json

@@ -111,6 +111,7 @@
     "wrap-ansi": "^10.0.0",
     "ws": "^8.20.0",
     "xss": "^1.0.15",
+    "xxhash-wasm": "^1.1.0",
     "yaml": "^2.8.3",
     "zod": "^4.3.6"
   },