feat(subscribe): update inventory logic in subscribe table and add migration scripts

initialize/migrate/database/02125_subscribe_stock.down.sql

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+
+-- This migration script reverts the inventory values in the 'subscribe' table
+UPDATE `subscribe`
+SET `inventory` = 0
+WHERE `inventory` = -1;

initialize/migrate/database/02125_subscribe_stock.up.sql

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+-- Update the `subscribe` table to set `inventory` to -1 where it is currently 0
+UPDATE `subscribe`
+SET `inventory` = -1
+WHERE `inventory` = 0;