fix: persist guest/redemption activation context to DB to survive Redis TTL expiry (Bug 1 + Bug 10)

- Add `activation_context` TEXT column to `order` table (migration 02150)
- purchaseLogic: write TemporaryOrderInfo JSON to order.ActivationContext in the same
  insert transaction; Redis write is now best-effort (non-fatal)
- redeemCodeLogic: write redemption {type, redemption_code_id, unit_time, quantity} JSON
  to order.ActivationContext at order creation; Redis write is now best-effort (non-fatal)
- getTempOrderInfo: on Redis miss, fall back to order.ActivationContext from DB;
  logs CRITICAL and returns error if both are missing (old orders with no DB record)
- RedemptionActivate: on Redis miss, fall back to order.ActivationContext from DB;
  same CRITICAL log path for legacy orders

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

initialize/migrate/database/02150_order_activation_context.down.sql

@@ -0,0 +1,2 @@
+-- Remove activation_context column from order table
+ALTER TABLE `order` DROP COLUMN IF EXISTS `activation_context`;