feat: add local signup and Kakao verification gate

packages/infra/prisma/gateway-migrations/20260726000000_add_local_signup_verification/migration.sql

@@ -0,0 +1,26 @@
+ALTER TABLE "app_user"
+    ADD COLUMN "terms_accepted_at" TIMESTAMP(3),
+    ADD COLUMN "privacy_accepted_at" TIMESTAMP(3),
+    ADD COLUMN "kakao_verified_at" TIMESTAMP(3),
+    ADD COLUMN "kakao_grace_started_at" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP;
+
+UPDATE "app_user"
+SET "kakao_verified_at" = COALESCE("updated_at", "created_at")
+WHERE "oauth_type" = 'KAKAO'
+  AND "kakao_verified_at" IS NULL;
+
+DO $$
+BEGIN
+    IF EXISTS (
+        SELECT 1
+        FROM "app_user"
+        GROUP BY "display_name"
+        HAVING COUNT(*) > 1
+    ) THEN
+        RAISE EXCEPTION
+            'Cannot enforce unique app_user.display_name: resolve duplicate display names before applying this migration.';
+    END IF;
+END
+$$;
+
+CREATE UNIQUE INDEX "app_user_display_name_key" ON "app_user"("display_name");

packages/infra/prisma/gateway.prisma

@@ -53,7 +53,7 @@ enum GatewaySourceMode {
 model AppUser {
   id            String    @id @default(uuid())
   loginId       String    @unique @map("login_id")
-  displayName   String    @map("display_name")
+  displayName   String    @unique @map("display_name")
   passwordHash  String    @map("password_hash")
   passwordSalt  String    @map("password_salt")
   roles         Json      @default(dbgenerated("'[]'::jsonb"))
@@ -66,6 +66,10 @@ model AppUser {
   imageServer   Int       @default(0) @map("image_server")
   iconUpdatedAt DateTime? @map("icon_updated_at")
   thirdPartyUse Boolean   @default(true) @map("third_party_use")
+  termsAcceptedAt DateTime? @map("terms_accepted_at")
+  privacyAcceptedAt DateTime? @map("privacy_accepted_at")
+  kakaoVerifiedAt DateTime? @map("kakao_verified_at")
+  kakaoGraceStartedAt DateTime @default(now()) @map("kakao_grace_started_at")
   deleteAfter   DateTime? @map("delete_after")
   createdAt     DateTime  @default(now()) @map("created_at")
   updatedAt     DateTime  @updatedAt @map("updated_at")