- Rename UI labels from "Addons Manager" to "Server Content Manager"
- Add server_content_categories.php: central category map with 8 types
- Bump module db_version 1→2 with safe VARCHAR(32) migration for addon_type
- addons_manager.php: use category map for type list + comments
- addons_installer.php: use category map + full TODO blocks for Phase 2+
- user_addons.php: dynamic category iteration via category map
- monitor_buttons.php: updated header comment
- English lang: updated all user-visible strings, added new type labels
- global.php + gamemanager.php: updated LANG_addons_manager, LANG_user_addons, LANG_addons
- Created SERVER_CONTENT_ROADMAP.md with full review and migration plan
Agent-Logs-Url: https://github.com/GameServerPanel/GSP/sessions/1e8f1b08-96d6-4c47-8f27-efe972d7cf17
Co-authored-by: iaretechnician <2749183+iaretechnician@users.noreply.github.com>