Fix race create sessione su CPX: ready solo dopo MediaMTX.

I nodi cloud restano in provisioning finché :9997 risponde; retry su create_path e 503 retryable se l’ingest è ancora irraggiungibile.

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

backend/spec/services/streams/autoscaler_spec.rb

@@ -224,4 +224,41 @@ RSpec.describe Streams::Autoscaler do
       expect(described_class.within_budget?(1)).to eq(false)
     end
   end
+
+  it "promotes provisioning nodes when MediaMTX becomes reachable" do
+    with_env(
+      "STREAM_AUTOSCALE_ENABLED" => "1",
+      "STREAM_AUTOSCALE_WARM_SPARE" => "0",
+      "STREAM_AUTOSCALE_SOFT_FREE_SLOTS" => "0",
+      "STREAM_AUTOSCALE_KIND" => "lab",
+      "MEDIAMTX_API_URL" => "http://mtx-home:9997",
+      "MEDIAMTX_RTMP_URL" => "rtmp://home.example:1935",
+      "HLS_PUBLIC_URL" => "https://home.example/hls"
+    ) do
+      Streams::NodeRegistry.ensure_home_from_env!
+      node = StreamNode.create!(
+        slug: "ingest-lab-prov",
+        hostname: "prov.lab",
+        role: "lab",
+        status: "provisioning",
+        provider: "local",
+        rtmp_base_url: "rtmp://h:1935",
+        hls_base_url: "https://h/hls",
+        api_base_url: "http://h:9997",
+        max_publishers: 2,
+        max_relays: 2
+      )
+      allow(Streams::NodeHealth).to receive(:promote_if_healthy!) do |n|
+        n.update!(status: "ready", last_health_at: Time.current)
+        true
+      end
+
+      provisioner = instance_double(Streams::NodeProvisioner)
+      expect(provisioner).not_to receive(:provision_lab!)
+
+      result = described_class.reconcile!(provisioner: provisioner)
+      expect(result.actions).to include(:"ready_ingest-lab-prov")
+      expect(node.reload.status).to eq("ready")
+    end
+  end
 end