fix: Rename player_sessions migration to 006 (avoid collision with 004_status_page)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

backend/migrations/004_status_page_description.sql

@@ -0,0 +1,5 @@
+-- Add status_page_description column to public_site_config
+-- Supports custom server descriptions on the public status page
+
+ALTER TABLE public_site_config
+ADD COLUMN IF NOT EXISTS status_page_description TEXT;