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/app/models/concerns/brandable.rb

@@ -0,0 +1,43 @@
+module Brandable
+  extend ActiveSupport::Concern
+
+  HEX_COLOR = /\A#[0-9A-Fa-f]{6}\z/
+
+  included do
+    has_one_attached :logo_file
+    validates :primary_color, format: { with: HEX_COLOR }, allow_blank: true
+    validates :secondary_color, format: { with: HEX_COLOR }, allow_blank: true
+  end
+
+  def effective_primary_color
+    primary_color.presence || default_primary_color
+  end
+
+  def effective_secondary_color
+    secondary_color.presence || default_secondary_color
+  end
+
+  def effective_logo_url
+    if logo_file.attached?
+      Rails.application.routes.url_helpers.rails_blob_path(logo_file, only_path: true)
+    elsif logo_url.present?
+      logo_url
+    else
+      branding_parent&.effective_logo_url
+    end
+  end
+
+  private
+
+  def default_primary_color
+    "#e53935"
+  end
+
+  def default_secondary_color
+    "#ffffff"
+  end
+
+  def branding_parent
+    nil
+  end
+end