feat: CatalogAdmin server handlers (10050-10059) with acc_catalogfurni

Add 9 incoming packet handlers + 1 outgoing composer for catalog
admin management via websocket. All operations require acc_catalogfurni
permission.

Handlers:
- CatalogAdminSavePageEvent (10050) - UPDATE catalog_pages
- CatalogAdminCreatePageEvent (10051) - INSERT catalog_pages
- CatalogAdminDeletePageEvent (10052) - DELETE catalog_pages
- CatalogAdminSaveOfferEvent (10053) - UPDATE catalog_items
- CatalogAdminCreateOfferEvent (10054) - INSERT catalog_items
- CatalogAdminDeleteOfferEvent (10055) - DELETE catalog_items
- CatalogAdminMoveOfferEvent (10056) - reorder offers
- CatalogAdminMovePageEvent (10057) - move/toggle enabled/visible
- CatalogAdminPublishEvent (10058) - reload catalog + broadcast
- CatalogAdminResultComposer (10059) - response (success + message)

Includes:
- New permission constant ACC_CATALOGFURNI in Permission.java
- SQL migration to add acc_catalogfurni column to permissions table
- Enabled by default for Administrator rank (id=7)

Emulator/sqlupdates/catalog_admin_permission.sql

@@ -0,0 +1,17 @@
+-- ============================================================
+-- Catalog & Furni Admin Permission
+-- Adds acc_catalogfurni permission to the permissions table
+-- Required by: CatalogAdmin packet handlers (10050-10059)
+-- ============================================================
+
+-- 1. Add the column to the permissions table
+ALTER TABLE `permissions`
+    ADD COLUMN `acc_catalogfurni` ENUM('0','1') NOT NULL DEFAULT '0'
+    AFTER `acc_catalog_ids`;
+
+-- 2. Enable for Administrator (rank 7) by default
+UPDATE `permissions` SET `acc_catalogfurni` = '1' WHERE `id` = 7;
+
+-- Optional: enable for other ranks as needed
+-- UPDATE `permissions` SET `acc_catalogfurni` = '1' WHERE `id` = 6; -- Super Mod
+-- UPDATE `permissions` SET `acc_catalogfurni` = '1' WHERE `id` = 5; -- Moderator