Bump ai and agents

Bumps [ai](https://github.com/vercel/ai) to 5.0.89 and updates ancestor dependency [agents](https://github.com/cloudflare/agents/tree/HEAD/packages/agents). These dependencies need to be updated together.


Updates `ai` from 4.3.19 to 5.0.89
- [Release notes](https://github.com/vercel/ai/releases)
- [Changelog](https://github.com/vercel/ai/blob/main/CHANGELOG.md)
- [Commits](https://github.com/vercel/ai/compare/ai@4.3.19...ai@5.0.89)

Updates `agents` from 0.0.113 to 0.2.23
- [Release notes](https://github.com/cloudflare/agents/releases)
- [Changelog](https://github.com/cloudflare/agents/blob/main/packages/agents/CHANGELOG.md)
- [Commits](https://github.com/cloudflare/agents/commits/agents@0.2.23/packages/agents)

---
updated-dependencies:
- dependency-name: ai
  dependency-version: 5.0.89
  dependency-type: indirect
- dependency-name: agents
  dependency-version: 0.2.23
  dependency-type: direct:production
...

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Author: dependabot[bot]