feature: onboarding emails

* wip

* wip

* wip

* fix coderabbit comments

* remove template

packages/db/prisma/migrations/20260121071611_add_unsubscribe_email/migration.sql

@@ -0,0 +1,12 @@
+-- CreateTable
+CREATE TABLE "public"."email_unsubscribes" (
+    "id" UUID NOT NULL DEFAULT gen_random_uuid(),
+    "email" TEXT NOT NULL,
+    "category" TEXT NOT NULL,
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+
+    CONSTRAINT "email_unsubscribes_pkey" PRIMARY KEY ("id")
+);
+
+-- CreateIndex
+CREATE UNIQUE INDEX "email_unsubscribes_email_category_key" ON "public"."email_unsubscribes"("email", "category");