chore: rename activation context migration to 02151

Co-authored-by: multica-agent <github@multica.ai>

initialize/migrate/database/02151_order_activation_context.up.sql

@@ -0,0 +1,6 @@
+-- Add activation_context column to order table for Redis fallback persistence (idempotent)
+SET @col_exists = (SELECT COUNT(*) FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = 'order' AND COLUMN_NAME = 'activation_context');
+SET @sql = IF(@col_exists = 0, 'ALTER TABLE `order` ADD COLUMN `activation_context` TEXT DEFAULT NULL COMMENT ''Activation context JSON (guest/redemption info for DB fallback)'' AFTER `app_account_token`', 'SELECT 1');
+PREPARE stmt FROM @sql;
+EXECUTE stmt;
+DEALLOCATE PREPARE stmt;