feat(fayda): implement verifayda oidc service

apps/edr-passenger-api/src/modules/verifayda/verifayda.errors.ts

@@ -0,0 +1,19 @@
+import { BadGatewayException, ConflictException } from '@nestjs/common';
+
+export class FaydaTokenExchangeException extends BadGatewayException {
+  constructor(message = 'Fayda token exchange failed') {
+    super({ code: 'FAYDA_TOKEN_EXCHANGE_FAILED', message });
+  }
+}
+
+export class FaydaUserInfoException extends BadGatewayException {
+  constructor(message = 'Fayda userinfo fetch failed') {
+    super({ code: 'FAYDA_USERINFO_FAILED', message });
+  }
+}
+
+export class FaydaIdentityConflictException extends ConflictException {
+  constructor(message = 'This Fayda identity is already linked to another account') {
+    super({ code: 'FAYDA_IDENTITY_CONFLICT', message });
+  }
+}