chore: relocate backend into apps/api ahead of monorepo merge

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/api/database/migrations/20270101000028-create-plan-policies.js

@@ -0,0 +1,21 @@
+'use strict';
+
+// badge_* columns (badge_asset_id/label/description/information) were
+// dropped by 20260101000064 — badge config now lives on tier_categories.
+module.exports = {
+  async up(queryInterface, Sequelize) {
+    await queryInterface.createTable('plan_policies', {
+      policy_id:    { type: Sequelize.BIGINT, primaryKey: true, autoIncrement: true },
+      plan_id:      { type: Sequelize.BIGINT, allowNull: false, unique: true,
+                      references: { model: 'tier_plans', key: 'plan_id' },
+                      onUpdate: 'CASCADE', onDelete: 'CASCADE' },
+      access_rules: { type: Sequelize.JSONB, allowNull: false, defaultValue: [] },
+      createdAt:    { type: Sequelize.DATE, allowNull: false },
+      updatedAt:    { type: Sequelize.DATE, allowNull: false },
+    });
+  },
+
+  async down(queryInterface) {
+    await queryInterface.dropTable('plan_policies');
+  },
+};