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/ipc/shared/language_model_helpers.ts

@@ -211,6 +211,40 @@ export const MODEL_OPTIONS: Record<string, ModelOption[]> = {
       temperature: 0,
     },
   ],
+  azure: [
+    {
+      name: "gpt-5",
+      displayName: "GPT-5",
+      description: "Azure OpenAI GPT-5 model with reasoning capabilities",
+      maxOutputTokens: 128_000,
+      contextWindow: 400_000,
+      temperature: 0,
+    },
+    {
+      name: "gpt-5-mini",
+      displayName: "GPT-5 Mini",
+      description: "Azure OpenAI GPT-5 Mini model",
+      maxOutputTokens: 128_000,
+      contextWindow: 400_000,
+      temperature: 0,
+    },
+    {
+      name: "gpt-5-nano",
+      displayName: "GPT-5 Nano",
+      description: "Azure OpenAI GPT-5 Nano model",
+      maxOutputTokens: 128_000,
+      contextWindow: 400_000,
+      temperature: 0,
+    },
+    {
+      name: "gpt-5-chat",
+      displayName: "GPT-5 Chat",
+      description: "Azure OpenAI GPT-5 Chat model",
+      maxOutputTokens: 16_384,
+      contextWindow: 128_000,
+      temperature: 0,
+    },
+  ],
 };
 
 export const PROVIDER_TO_ENV_VAR: Record<string, string> = {
@@ -218,6 +252,7 @@ export const PROVIDER_TO_ENV_VAR: Record<string, string> = {
   anthropic: "ANTHROPIC_API_KEY",
   google: "GEMINI_API_KEY",
   openrouter: "OPENROUTER_API_KEY",
+  azure: "AZURE_API_KEY",
 };
 
 export const CLOUD_PROVIDERS: Record<
@@ -258,6 +293,12 @@ export const CLOUD_PROVIDERS: Record<
     websiteUrl: "https://academy.dyad.sh/settings",
     gatewayPrefix: "dyad/",
   },
+  azure: {
+    displayName: "Azure OpenAI",
+    hasFreeTier: false,
+    websiteUrl: "https://portal.azure.com/",
+    gatewayPrefix: "",
+  },
 };
 
 const LOCAL_PROVIDERS: Record<