🔑 [feat] Add API key retrieval for multiple providers

- Implement getOpenAIAPIKey function for OpenAI API
- Add getAWSCredentials function for AWS Bedrock

app/lib/.server/llm/api-key.ts

@@ -1,9 +1,17 @@
 import { env } from 'node:process';
 
 export function getAPIKey(cloudflareEnv: Env) {
-  /**
-   * The `cloudflareEnv` is only used when deployed or when previewing locally.
-   * In development the environment variables are available through `env`.
-   */
   return env.ANTHROPIC_API_KEY || cloudflareEnv.ANTHROPIC_API_KEY;
 }
+
+export function getOpenAIAPIKey(cloudflareEnv: Env) {
+  return env.OPENAI_API_KEY || cloudflareEnv.OPENAI_API_KEY;
+}
+
+export function getAWSCredentials(cloudflareEnv: Env) {
+  return {
+    accessKeyId: env.AWS_ACCESS_KEY_ID || cloudflareEnv.AWS_ACCESS_KEY_ID,
+    secretAccessKey: env.AWS_SECRET_ACCESS_KEY || cloudflareEnv.AWS_SECRET_ACCESS_KEY,
+    region: env.AWS_REGION || cloudflareEnv.AWS_REGION || 'ap-northeast-1'
+  };
+}