Update deprecated gpt-4o-mini model to gpt-4.1-mini

[diberry]

Context

The gpt-4o-mini Standard model was deprecated on 2026-03-31. The GlobalStandard variant has 0 quota available.

Solution

Replace gpt-4o-mini references with gpt-4.1-mini (Standard, v2025-04-14).

Files to Update

This issue is specifically for the sample code and infrastructure in the documentdb-samples repo:

• Bicep/infrastructure files that reference gpt-4o-mini
• Code samples (JavaScript, Python, Go, etc.) with hardcoded model names
• README files with model configuration examples
• .env.example or environment template files
• Any documentation within this repo

Related Documentation Updates

The following Azure documentation articles were already updated in MicrosoftDocs/azure-databases-docs-pr PR #4727:

• �rticles/documentdb/quickstart-agent-nodejs.md (4 references fixed)
• �rticles/documentdb/quickstart-agent-go.md (2 references fixed)

This issue focuses on the sample code repository itself.

Acceptance Criteria

• All references to gpt-4o-mini in code, config, and documentation updated to gpt-4.1-mini
• Samples tested to ensure they work with the new model
• Any deployment guides or documentation updated