feat: enhance configuration management and add error handling

src/errors.ts

@@ -0,0 +1,42 @@
+export class AppError extends Error {
+  constructor(
+    message: string,
+    public code: string,
+    public statusCode: number = 500,
+  ) {
+    super(message);
+    this.name = "AppError";
+    Error.captureStackTrace(this, this.constructor);
+  }
+}
+
+export class ConfigError extends AppError {
+  constructor(message: string) {
+    super(message, "CONFIG_ERROR", 500);
+    this.name = "ConfigError";
+  }
+}
+
+export class AudioError extends AppError {
+  constructor(message: string) {
+    super(message, "AUDIO_ERROR", 500);
+    this.name = "AudioError";
+  }
+}
+
+export class VoiceConnectionError extends AppError {
+  constructor(message: string) {
+    super(message, "VOICE_CONNECTION_ERROR", 500);
+    this.name = "VoiceConnectionError";
+  }
+}
+
+export class ValidationError extends AppError {
+  constructor(
+    message: string,
+    public details?: Record<string, string[]>,
+  ) {
+    super(message, "VALIDATION_ERROR", 400);
+    this.name = "ValidationError";
+  }
+}