fix: move undici from devDependencies to dependencies

undici is imported at runtime in App.tsx for the custom keepAlive
Agent.  When bundled with --packages=external, end users need the
package installed — it cannot be a devDependency.

Author: Lellansin

package-lock.json

@@ -48,6 +48,7 @@
     "ink-gradient": "^4.0.0",
     "openai": "^6.35.0",
     "react": "^19.2.5",
+    "undici": "^8.3.0",
     "zod": "^4.4.3"
   },
   "devDependencies": {
@@ -65,7 +66,6 @@
     "prettier": "^3.8.3",
     "tsx": "^4.21.0",
     "typescript": "^6.0.3",
-    "typescript-eslint": "^8.59.2",
-    "undici": "^8.3.0"
+    "typescript-eslint": "^8.59.2"
   }
 }