Club come entità principale, branding e fix infrastruttura streaming.

Introduce clubs con abbonamento, branding Active Storage e flusso registrazione società; corregge healthcheck MediaMTX (immagine distroless) e allinea dominio produzione matchlivetv.it.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/db/migrate/20260527160100_move_subscriptions_to_clubs.rb

@@ -0,0 +1,32 @@
+class MoveSubscriptionsToClubs < ActiveRecord::Migration[7.2]
+  def up
+    unless column_exists?(:subscriptions, :club_id)
+      add_reference :subscriptions, :club, type: :uuid, foreign_key: true, index: { unique: true }
+    end
+
+    execute <<~SQL.squish
+      UPDATE subscriptions SET club_id = teams.club_id
+      FROM teams WHERE subscriptions.team_id = teams.id AND subscriptions.club_id IS NULL
+    SQL
+
+    if column_exists?(:subscriptions, :team_id)
+      remove_index :subscriptions, :team_id if index_exists?(:subscriptions, :team_id)
+      remove_reference :subscriptions, :team
+    end
+
+    change_column_null :subscriptions, :club_id, false if column_exists?(:subscriptions, :club_id)
+  end
+
+  def down
+    add_reference :subscriptions, :team, type: :uuid, foreign_key: true, index: { unique: true } unless column_exists?(:subscriptions, :team_id)
+
+    execute <<~SQL.squish
+      UPDATE subscriptions SET team_id = (
+        SELECT teams.id FROM teams WHERE teams.club_id = subscriptions.club_id ORDER BY teams.created_at LIMIT 1
+      )
+    SQL
+
+    remove_reference :subscriptions, :club if column_exists?(:subscriptions, :club_id)
+    change_column_null :subscriptions, :team_id, false
+  end
+end