Add shipping cost groups and reject spam contact-form SMS.

Wire cart/checkout shipping fees with category groups and static rates, reject gibberish contact submissions, and SMS only valid Iranian mobiles.

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

database/migrations/100_shipping_cost_groups.sql

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+-- Shipping cost groups (هزینه ارسال) + per-city overrides + category assignment
+
+CREATE TABLE IF NOT EXISTS shipping_cost_groups (
+  id BIGSERIAL PRIMARY KEY,
+  business_id BIGINT NOT NULL REFERENCES businesses (id) ON DELETE CASCADE ON UPDATE NO ACTION,
+  name VARCHAR(255) NOT NULL,
+  name_en VARCHAR(255) NOT NULL,
+  description TEXT NULL,
+  methods TEXT[] NOT NULL DEFAULT '{}',
+  default_amount NUMERIC(12, 2) NOT NULL DEFAULT 0,
+  sort_order INT NOT NULL DEFAULT 0,
+  is_active BOOLEAN NOT NULL DEFAULT TRUE,
+  created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+  updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_shipping_cost_groups_business_id
+  ON shipping_cost_groups (business_id);
+
+CREATE INDEX IF NOT EXISTS idx_shipping_cost_groups_business_sort_order
+  ON shipping_cost_groups (business_id, sort_order);
+
+DROP TRIGGER IF EXISTS shipping_cost_groups_set_updated_at ON shipping_cost_groups;
+CREATE TRIGGER shipping_cost_groups_set_updated_at
+  BEFORE UPDATE ON shipping_cost_groups
+  FOR EACH ROW
+  EXECUTE FUNCTION set_updated_at();
+
+CREATE TABLE IF NOT EXISTS shipping_cost_group_city_rates (
+  id BIGSERIAL PRIMARY KEY,
+  shipping_cost_group_id BIGINT NOT NULL REFERENCES shipping_cost_groups (id) ON DELETE CASCADE ON UPDATE NO ACTION,
+  city_id BIGINT NOT NULL REFERENCES cities (id) ON DELETE CASCADE ON UPDATE NO ACTION,
+  amount NUMERIC(12, 2) NOT NULL,
+  created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+  updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+  CONSTRAINT shipping_cost_group_city_rates_unique UNIQUE (shipping_cost_group_id, city_id)
+);
+
+CREATE INDEX IF NOT EXISTS idx_shipping_cost_group_city_rates_group_id
+  ON shipping_cost_group_city_rates (shipping_cost_group_id);
+
+CREATE INDEX IF NOT EXISTS idx_shipping_cost_group_city_rates_city_id
+  ON shipping_cost_group_city_rates (city_id);
+
+DROP TRIGGER IF EXISTS shipping_cost_group_city_rates_set_updated_at ON shipping_cost_group_city_rates;
+CREATE TRIGGER shipping_cost_group_city_rates_set_updated_at
+  BEFORE UPDATE ON shipping_cost_group_city_rates
+  FOR EACH ROW
+  EXECUTE FUNCTION set_updated_at();
+
+CREATE TABLE IF NOT EXISTS shipping_cost_group_categories (
+  shipping_cost_group_id BIGINT NOT NULL REFERENCES shipping_cost_groups (id) ON DELETE CASCADE ON UPDATE NO ACTION,
+  category_id BIGINT NOT NULL REFERENCES categories (id) ON DELETE CASCADE ON UPDATE NO ACTION,
+  PRIMARY KEY (shipping_cost_group_id, category_id)
+);
+
+CREATE INDEX IF NOT EXISTS idx_shipping_cost_group_categories_category_id
+  ON shipping_cost_group_categories (category_id);