Summary

Fix the Azure OpenAI regression reported in #13499.

Dated Azure API versions such as 2024-12-01-preview are intended to stay on Cherry's chat / deployment-based path, while only generic preview / v1 should use the Responses API. The regression was that aiCore's internal azure provider still defaulted to the Responses transport, so deployment-based Azure requests could still generate /openai/deployments/<deployment>/responses URLs and fail with 404.

This PR restores the intended split by:

• making the azure provider default to provider.chat(...)
• keeping azure-responses on provider.responses(...)
• aligning the registry's azure-chat fallback with the same chat wrapper
• adding regression coverage for provider routing and registry behavior

Verification

• node node_modules/vitest/vitest.mjs run --project renderer src/renderer/src/aiCore/provider/__tests__/providerConfig.test.ts
• node node_modules/vitest/vitest.mjs run --project aiCore packages/aiCore/src/core/providers/__tests__/registry-functionality.test.ts

Fixes #13499