fix(GRO-1533): add missing coat_type/pet_size_category columns in migration 0031

Migration 0031 tries to ALTER the coat_type and pet_size_category columns
on the pets table to use new enum types, but no prior migration adds
these columns. On a fresh DB (after the reset CronJob wiped all tables),
this causes the entire migration chain to fail and roll back.

Added ADD COLUMN IF NOT EXISTS before the ALTER TYPE so the migration
works both on fresh databases and existing ones with the columns.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

packages/db/migrations/0031_buffer_rules.sql

@@ -6,8 +6,10 @@
 CREATE TYPE "pet_size_category" AS ENUM ('small', 'medium', 'large', 'xlarge');
 CREATE TYPE "coat_type" AS ENUM ('smooth', 'double', 'wire', 'curly', 'long', 'hairless');
 
--- ─── Alter pets columns to use new enums ─────────────────────────────────────
+-- ─── Add columns to pets if missing, then cast to enums ──────────────────────
 
+ALTER TABLE "pets" ADD COLUMN IF NOT EXISTS "coat_type" text;
+ALTER TABLE "pets" ADD COLUMN IF NOT EXISTS "pet_size_category" text;
 ALTER TABLE "pets" ALTER COLUMN "coat_type" TYPE "coat_type" USING "coat_type"::text::"coat_type";
 ALTER TABLE "pets" ALTER COLUMN "pet_size_category" TYPE "pet_size_category" USING "pet_size_category"::text::"pet_size_category";