Add twilio softphone with integrated AI assistant

backend/src/voice/interfaces/integration-config.interface.ts

@@ -0,0 +1,20 @@
+export interface TwilioConfig {
+  accountSid: string;
+  authToken: string;
+  phoneNumber: string;
+  apiKey?: string;  // API Key SID for generating access tokens
+  apiSecret?: string;  // API Key Secret
+  twimlAppSid?: string;  // TwiML App SID for Voice SDK
+}
+
+export interface OpenAIConfig {
+  apiKey: string;
+  assistantId?: string;
+  model?: string;
+  voice?: string;
+}
+
+export interface IntegrationsConfig {
+  twilio?: TwilioConfig;
+  openai?: OpenAIConfig;
+}