revert: remove remaining code-index embedder changes

- Remove src/services/code-index/embedders/index.ts
- Revert AvailableEmbedders type change in embedder.ts

Author: daniel-lxs

src/services/code-index/embedders/index.ts

@@ -28,7 +28,7 @@ export interface EmbeddingResponse {
 	}
 }
 
-export type AvailableEmbedders = "openai" | "ollama" | "openai-compatible" | "gemini" | "mistral" | "doubao"
+export type AvailableEmbedders = "openai" | "ollama" | "openai-compatible" | "gemini" | "mistral"
 
 export interface EmbedderInfo {
 	name: AvailableEmbedders