fix(helpdesk): add software-products.manage permission to admin role seed

The new permission was missing from the admin role seed in init.sql and
needed an idempotent update script for existing installations.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

db/updates/2026-04-14-helpdesk-software-products-permission.sql

@@ -0,0 +1,9 @@
+-- Helpdesk module: assign software products permission to Admin role.
+-- Idempotent: safe to run multiple times.
+
+INSERT INTO `role_permissions` (`role_id`, `permission_id`, `created`)
+SELECT r.id, p.id, NOW()
+FROM roles r
+JOIN permissions p ON p.`key` = 'helpdesk.software-products.manage'
+WHERE r.description IN ('Admin', 'Administrator') OR r.id = 1
+ON DUPLICATE KEY UPDATE role_id = role_id;