Initialize repository for autorest build 20250821.4

Author: azure-sdk

eng/Packages.Data.props

@@ -293,7 +293,7 @@
     All should have PrivateAssets="All" set so they don't become package dependencies
   -->
   <ItemGroup>
-    <PackageReference Update="Microsoft.Azure.AutoRest.CSharp" Version="3.0.0-beta.20250821.2" PrivateAssets="All" />
+    <PackageReference Update="Microsoft.Azure.AutoRest.CSharp" Version="3.0.0-alpha.20250821.4" PrivateAssets="All" />
     <PackageReference Update="Azure.ClientSdk.Analyzers" Version="0.1.1-dev.20250715.1" PrivateAssets="All" />
     <PackageReference Update="coverlet.collector" Version="3.2.0" PrivateAssets="All" />
     <!-- Note: Upgrading the .NET SDK version needs to be synchronized with the autorest.csharp repository -->

eng/emitter-package-lock.json

@@ -1,7 +1,7 @@
 {
   "main": "dist/src/index.js",
   "dependencies": {
-    "@azure-tools/typespec-csharp": "0.2.0-beta.20250821.2"
+    "@azure-tools/typespec-csharp": "https://pkgs.dev.azure.com/azure-sdk/public/_packaging/azure-sdk-for-js-test-autorest/npm/registry/@azure-tools/typespec-csharp/-/typespec-csharp-0.2.0-alpha.20250821.4.tgz"
   },
   "devDependencies": {
     "@azure-tools/typespec-autorest": "0.59.0",
@@ -19,5 +19,8 @@
     "@typespec/streams": "0.73.0",
     "@typespec/versioning": "0.73.0",
     "@typespec/xml": "0.73.0"
+  },
+  "overrides": {
+    "@autorest/csharp": "https://pkgs.dev.azure.com/azure-sdk/public/_packaging/azure-sdk-for-js-test-autorest/npm/registry/@autorest/csharp/-/csharp-3.0.0-alpha.20250821.4.tgz"
   }
 }