Add optional SMS auto-block threshold below balance.

Co-authored-by: Cursor <cursoragent@cursor.com>

prisma/migrations/20260808140000_sms_auto_block_below/migration.sql

@@ -0,0 +1,2 @@
+-- AlterTable
+ALTER TABLE `sms_accounts` ADD COLUMN `auto_block_below_rials` INTEGER NULL;

prisma/schema.prisma

@@ -89,6 +89,8 @@ model SmsAccount {
   balanceRials        Int      @default(0) @map("balance_rials")
   pricePerPartRials   Int      @default(2500) @map("price_per_part_rials")
   isBlocked           Boolean  @default(false) @map("is_blocked")
+  /// If set: block non-alert SMS when balanceRials < this. Null = only manual isBlocked.
+  autoBlockBelowRials Int?     @map("auto_block_below_rials")
   /// below this => red/critical
   alertCriticalRials  Int      @default(10000) @map("alert_critical_rials")
   /// at/below this (and above critical) => yellow; above => green