Add Mellat e-payment, videos/instructions CMS, and legacy domain lookup.

Store gateway credentials per business, initiate/verify Mellat at checkout, and resolve old CMS ids from domains in the migrate modal.

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

database/migrations/062_payment_gateway_fields.sql

@@ -0,0 +1,14 @@
+-- Meshkee CMS — e-payment gateway tracking on transactions
+
+ALTER TABLE transactions
+  ADD COLUMN IF NOT EXISTS gateway_ref VARCHAR(255),
+  ADD COLUMN IF NOT EXISTS gateway_track_id VARCHAR(255),
+  ADD COLUMN IF NOT EXISTS gateway_meta JSONB;
+
+CREATE INDEX IF NOT EXISTS idx_transactions_gateway_ref
+  ON transactions (business_id, gateway_ref)
+  WHERE gateway_ref IS NOT NULL;
+
+CREATE INDEX IF NOT EXISTS idx_transactions_gateway_track
+  ON transactions (business_id, gateway_track_id)
+  WHERE gateway_track_id IS NOT NULL;