feat(provider/gateway): Add o3-deep-research to gateway model string autocomplete (#10031)

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## Background
Adding o3-deep-research to AI Gateway

## Summary
Add o3-deep-research to gateway model string autocomplete

## Manual Verification
Autocomplete works

## Checklist

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- [ ] Tests have been added / updated (for bug fixes / features)
- [ ] Documentation has been added / updated (for bug fixes / features)
- [X] A _patch_ changeset for relevant packages has been added (for bug
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Author: R-Taneja

.changeset/eighty-terms-peel.md

@@ -0,0 +1,5 @@
+---
+'@ai-sdk/gateway': patch
+---
+
+feat(provider/gateway): Add o3-deep-research to gateway model string autocomplete

packages/gateway/src/gateway-language-model-settings.ts

@@ -90,6 +90,7 @@ export type GatewayModelId =
   | 'openai/gpt-oss-safeguard-20b'
   | 'openai/o1'
   | 'openai/o3'
+  | 'openai/o3-deep-research'
   | 'openai/o3-mini'
   | 'openai/o4-mini'
   | 'perplexity/sonar'