Pin C# API versions for enum rename migration

Keep C# generation on the existing SDK API versions while moving enum member names into TypeSpec.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: ArcturusZhang

specification/cosmos-db/resource-manager/Microsoft.DocumentDB/DocumentDB/tspconfig.yaml

@@ -59,7 +59,7 @@ options:
     enable-wire-path-attribute: true
     namespace: "Azure.ResourceManager.CosmosDB"
     emitter-output-dir: "{output-dir}/{service-dir}/{namespace}"
-    api-version: "2026-03-15"
+    api-version: "2026-04-01-preview"
 linter:
   extends:
     - "@azure-tools/typespec-azure-rulesets/resource-manager"

specification/eventhub/resource-manager/Microsoft.EventHub/Eventhub/tspconfig.yaml

@@ -57,6 +57,7 @@ options:
     namespace: "{package-name}"
     emitter-output-dir: "{output-dir}/{service-dir}/{namespace}"
     enable-wire-path-attribute: true
+    api-version: "2025-05-01-preview"
 linter:
   extends:
     - "@azure-tools/typespec-azure-rulesets/resource-manager"

specification/redisenterprise/resource-manager/Microsoft.Cache/RedisEnterprise/tspconfig.yaml

@@ -49,6 +49,7 @@ options:
     namespace: "Azure.ResourceManager.RedisEnterprise"
     emitter-output-dir: "{output-dir}/{service-dir}/{namespace}"
     enable-wire-path-attribute: true
+    api-version: "2025-08-01-preview"
 linter:
   extends:
     - "@azure-tools/typespec-azure-rulesets/resource-manager"