Add ApiStream generator to interface with providers

src/api/index.ts

@@ -1,5 +1,4 @@
 import { Anthropic } from "@anthropic-ai/sdk"
-import { Stream } from "@anthropic-ai/sdk/streaming"
 import { ApiConfiguration, ModelInfo } from "../shared/api"
 import { AnthropicHandler } from "./providers/anthropic"
 import { AwsBedrockHandler } from "./providers/bedrock"
@@ -9,15 +8,14 @@ import { OpenAiHandler } from "./providers/openai"
 import { OllamaHandler } from "./providers/ollama"
 import { GeminiHandler } from "./providers/gemini"
 import { OpenAiNativeHandler } from "./providers/openai-native"
-
-export type AnthropicStream = Stream<Anthropic.Beta.PromptCaching.Messages.RawPromptCachingBetaMessageStreamEvent>
+import { ApiStream } from "./transform/stream"
 
 export interface ApiHandler {
 	createMessage(
 		systemPrompt: string,
 		messages: Anthropic.Messages.MessageParam[],
 		tools: Anthropic.Messages.Tool[]
-	): Promise<AnthropicStream>
+	): ApiStream
 
 	getModel(): { id: string; info: ModelInfo }
 }