fix: ensure azure sets prompt cache key by default (#22957)

packages/opencode/src/provider/transform.ts

@@ -798,6 +798,7 @@ export function options(input: {
 
   if (input.model.api.npm === "@ai-sdk/azure") {
     result["store"] = true
+    result["promptCacheKey"] = input.sessionID
   }
 
   if (input.model.api.npm === "@openrouter/ai-sdk-provider") {