fix(provider): normalize missing array items in tool schemas

[mharris717]

Summary

• normalize tool schemas so array nodes missing items are converted to items: {} before they are sent to model providers
• preserve the original permissive schema semantics while avoiding OpenAI/OpenAI-compatible validation failures on MCP tools such as docker_create_container
• add a regression test for the nested ports -> additionalProperties -> anyOf -> array schema shape that triggered the bug

Testing

• bun test test/provider/transform.test.ts --timeout 30000
• push hook: bun turbo typecheck

[github-actions]

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[github-actions]

Thanks for your contribution!

This PR doesn't have a linked issue. All PRs must reference an existing issue.

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[github-actions]

The following comment was made by an LLM, it may be inaccurate:

I found a potentially related PR:

PR #20775: fix(opencode): sanitize array schemas missing items for all providers
#20775

This PR appears to be directly related to your current PR #21589. Both are addressing the issue of missing items in array schemas. You should check if #20775 already addresses the same problem or if it needs to be updated with your fix.

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