Refactor OpenAI adapter configuration and API key retrieval

- Updated the OpenAI adapter settings structure to nest the API key under an 'openai' object for better organization.
- Enhanced the API key retrieval logic in the SmartEmbedModelApiAdapter to prioritize adapter-specific settings, improving flexibility in configuration.
- Removed the deprecated API key getter in the SmartEmbedOpenAIAdapter, streamlining the codebase.

smart-embed-model/README.md

@@ -88,7 +88,9 @@ import { SmartEmbedOpenAIAdapter } from 'smart-embed-model/adapters/openai';
 const model = new SmartEmbedModel({
   model_key: 'text-embedding-3-small',
   settings: {
-    openai_api_key: 'YOUR_API_KEY'
+    openai: {
+      api_key: 'YOUR_API_KEY'
+    }
   },
   adapters: {
     openai: SmartEmbedOpenAIAdapter

smart-embed-model/adapters/_api.js

@@ -50,7 +50,7 @@ export class SmartEmbedModelApiAdapter extends SmartEmbedAdapter {
    * @returns {string} API key
    */
   get api_key() {
-    return this.settings.api_key || this.model_config.api_key;
+    return this.adapter_settings.api_key || this.settings.api_key || this.model_config.api_key;
   }
 
   /**

smart-embed-model/adapters/openai.js

@@ -111,11 +111,6 @@ export class SmartEmbedOpenAIAdapter extends SmartEmbedModelApiAdapter {
     return SmartEmbedOpenAIResponseAdapter;
   }
 
-  /** @returns {string} OpenAI API key */
-  get api_key() {
-    return this.settings.openai_api_key;
-  }
-
   /** @returns {number} Maximum tokens per input */
   get max_tokens() {
     return this.model_config.max_tokens || 8191;