started on adding openid login

prisma/migrations/20260128164514_add_oidc_user/migration.sql

@@ -0,0 +1,6 @@
+-- AlterTable
+ALTER TABLE "User" ADD COLUMN     "authProvider" TEXT,
+ADD COLUMN     "providerId" TEXT;
+
+-- CreateIndex
+CREATE INDEX "User_authProvider_providerId_idx" ON "User"("authProvider", "providerId");

prisma/schema.prisma

@@ -17,7 +17,12 @@ model User {
     events    Event[]  @relation("EventCreator")
     createdAt DateTime @default(now())
 
+    authProvider    String?   // 'credentials', 'oidc', 'google', etc.
+    providerId      String?   // OIDC subject ID
+
     FileUpload FileUpload[]
+
+    @@index([authProvider, providerId])
 }
 
 enum Role {