Add Azure OpenAI Custom Model Integration (#1001)

Fixes #710 

This PR implements comprehensive Azure OpenAI integration for Dyad,
enabling users to leverage Azure
OpenAI models through proper environment variable configuration. The
implementation adds Azure as a
supported provider with full integration into the existing language
model architecture, including support
  for GPT-5 models. Key features include environment-based
configuration using `AZURE_API_KEY` and `AZURE_RESOURCE_NAME`,
specialized UI components that provide clear
setup instructions and status indicators, and seamless integration with
Dyad's existing provider system.
The Azure provider leverages the @ai-sdk/azure package (v1.3.25) for
compatibility with the current
  TypeScript language model interfaces.

The implementation includes robust error handling for missing
configuration, comprehensive test coverage
with 9 new unit tests covering critical functionality like model client
creation and error scenarios, and
  an E2E test for the Azure-specific settings UI. 

<img width="1510" height="908" alt="Screenshot 2025-08-18 at 9 14 32 PM"
src="https://github.com/user-attachments/assets/04aa99e1-1590-4bb0-86c9-a67b97bc7500"
/>

---------

Co-authored-by: graphite-app[bot] <96075541+graphite-app[bot]@users.noreply.github.com>
Co-authored-by: Will Chen <willchen90@gmail.com>

src/components/settings/ApiKeyConfiguration.tsx

@@ -6,6 +6,7 @@ import {
   AccordionItem,
   AccordionTrigger,
 } from "@/components/ui/accordion";
+import { AzureConfiguration } from "./AzureConfiguration";
 import { Input } from "@/components/ui/input";
 import { Button } from "@/components/ui/button";
 import { UserSettings } from "@/lib/schemas";
@@ -46,6 +47,11 @@ export function ApiKeyConfiguration({
   onDeleteKey,
   isDyad,
 }: ApiKeyConfigurationProps) {
+  // Special handling for Azure OpenAI which requires environment variables
+  if (provider === "azure") {
+    return <AzureConfiguration envVars={envVars} />;
+  }
+
   const envApiKey = envVarName ? envVars[envVarName] : undefined;
   const userApiKey = settings?.providerSettings?.[provider]?.apiKey?.value;