Aggiunge registry nodi stream e provisioning Hetzner/lab per lo scale-out.

Prepara l'architettura multi-nodo (MediaMTX+ffmpeg) con assignment URL per sessione, admin di provision/drain e provider Cloud/DNS astratti verso mltv-stream.net.

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

backend/app/models/stream_node.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+# Nodo streaming (MediaMTX [+ relay ffmpeg]). Fase 0: registry + assignment URL.
+class StreamNode < ApplicationRecord
+  ROLES = %w[home cloud lab].freeze
+  STATUSES = %w[provisioning ready draining offline error].freeze
+  PROVIDERS = %w[local proxmox_lab hetzner].freeze
+
+  has_many :stream_sessions, dependent: :nullify
+
+  validates :slug, presence: true, uniqueness: true
+  validates :hostname, presence: true
+  validates :role, inclusion: { in: ROLES }
+  validates :status, inclusion: { in: STATUSES }
+  validates :provider, inclusion: { in: PROVIDERS }
+  validates :rtmp_base_url, :hls_base_url, :api_base_url, presence: true
+  validates :max_publishers, :max_relays, numericality: { greater_than: 0 }
+
+  scope :ready, -> { where(status: "ready") }
+  scope :allocatable, -> { ready }
+
+  # Sessioni che occupano uno slot path MediaMTX su questo nodo.
+  def occupying_sessions
+    stream_sessions.where(status: %w[idle connecting live reconnecting paused])
+  end
+
+  def active_publishers
+    occupying_sessions.count
+  end
+
+  def free_slots
+    [max_publishers - active_publishers, 0].max
+  end
+
+  def allocatable?
+    status == "ready" && free_slots.positive?
+  end
+end

backend/app/models/stream_session.rb

@@ -7,6 +7,7 @@ class StreamSession < ApplicationRecord
 
   belongs_to :match
   belongs_to :user
+  belongs_to :stream_node, optional: true
   has_many :stream_events, dependent: :destroy
   has_one :score_state, dependent: :destroy
   has_many :device_states, dependent: :destroy
@@ -74,7 +75,7 @@ class StreamSession < ApplicationRecord
   def rtmp_ingest_url
     # RootEncoder richiede rtmp://host:port/app/stream (due segmenti).
     # MediaMTX path = live/match_{uuid} (no ?token= nel path).
-    "#{MatchLiveTv.mediamtx_rtmp_url}/#{mediamtx_path_name}"
+    "#{rtmp_base_url.chomp('/')}/#{mediamtx_path_name}"
   end
 
   def mediamtx_path_name
@@ -90,8 +91,29 @@ class StreamSession < ApplicationRecord
   end
 
   def hls_playback_url
-    base = MatchLiveTv.hls_public_url.chomp("/")
-    "#{base}/#{effective_hls_path_name}/index.m3u8"
+    "#{hls_base_url.chomp('/')}/#{effective_hls_path_name}/index.m3u8"
+  end
+
+  def rtmp_base_url
+    stream_node&.rtmp_base_url.presence || MatchLiveTv.mediamtx_rtmp_url
+  end
+
+  def hls_base_url
+    stream_node&.hls_base_url.presence || MatchLiveTv.hls_public_url
+  end
+
+  def mediamtx_api_base_url
+    stream_node&.api_base_url.presence || MatchLiveTv.mediamtx_api_url
+  end
+
+  def mediamtx_internal_rtmp_url
+    stream_node&.internal_rtmp_url.presence ||
+      ENV.fetch("MEDIAMTX_INTERNAL_RTMP_URL", "rtmp://mediamtx:1935")
+  end
+
+  def mediamtx_internal_hls_url
+    stream_node&.internal_hls_url.presence ||
+      ENV.fetch("MEDIAMTX_HLS_URL", "http://mediamtx:8888")
   end
 
   def effective_hls_path_name