chore(deps)(deps): bump @ai-sdk/gateway from 3.0.139 to 4.0.4

Bumps [@ai-sdk/gateway](https://github.com/vercel/ai/tree/HEAD/packages/gateway) from 3.0.139 to 4.0.4.
- [Release notes](https://github.com/vercel/ai/releases)
- [Changelog](https://github.com/vercel/ai/blob/main/packages/gateway/CHANGELOG.md)
- [Commits](https://github.com/vercel/ai/commits/@ai-sdk/gateway@4.0.4/packages/gateway)

---
updated-dependencies:
- dependency-name: "@ai-sdk/gateway"
  dependency-version: 4.0.4
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

examples/app-todo/package.json

@@ -38,7 +38,7 @@
     "@objectstack/spec": "workspace:*"
   },
   "devDependencies": {
-    "@ai-sdk/gateway": "^3.0.139",
+    "@ai-sdk/gateway": "^4.0.4",
     "@objectstack/cli": "workspace:*",
     "ai": "^6.0.214",
     "tsx": "^4.22.4",

packages/cli/package.json

@@ -40,7 +40,7 @@
   },
   "dependencies": {
     "@ai-sdk/anthropic": "^3.0.89",
-    "@ai-sdk/gateway": "^3.0.139",
+    "@ai-sdk/gateway": "^4.0.4",
     "@ai-sdk/google": "^3.0.86",
     "@ai-sdk/openai": "^3.0.77",
     "@objectstack/account": "workspace:*",