fix #12: simplify auth adapter, add verifications table

src/lib/db/schema.ts

@@ -38,6 +38,15 @@ export const accounts = pgTable("accounts", {
   updatedAt: timestamp("updated_at", { withTimezone: true }).defaultNow().notNull(),
 });
 
+export const verifications = pgTable("verifications", {
+  id: text("id").primaryKey().$defaultFn(() => createId()),
+  identifier: text("identifier").notNull(),
+  value: text("value").notNull(),
+  expiresAt: timestamp("expires_at").notNull(),
+  createdAt: timestamp("created_at", { withTimezone: true }).defaultNow(),
+  updatedAt: timestamp("updated_at", { withTimezone: true }).defaultNow(),
+});
+
 export const comparisonStatusEnum = pgEnum("comparison_status", [
   "researching",
   "completed",