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/node_health_spec.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe Streams::NodeHealth do
+  let!(:node) do
+    StreamNode.create!(
+      slug: "ingest-health-01",
+      hostname: "ingest-health-01.mltv-stream.net",
+      role: "cloud",
+      status: "provisioning",
+      provider: "hetzner",
+      rtmp_base_url: "rtmp://h:1935",
+      hls_base_url: "https://h/hls",
+      api_base_url: "http://203.0.113.10:9997",
+      max_publishers: 4,
+      max_relays: 4
+    )
+  end
+
+  after { node.destroy }
+
+  it "promotes provisioning node when MediaMTX is reachable" do
+    client = instance_double(Mediamtx::Client, reachable?: true)
+    allow(Mediamtx::Client).to receive(:new).with(base_url: node.api_base_url).and_return(client)
+
+    expect(described_class.promote_if_healthy!(node)).to eq(true)
+    expect(node.reload.status).to eq("ready")
+    expect(node.last_health_at).to be_present
+  end
+
+  it "does not promote when MediaMTX is down" do
+    client = instance_double(Mediamtx::Client, reachable?: false)
+    allow(Mediamtx::Client).to receive(:new).with(base_url: node.api_base_url).and_return(client)
+
+    expect(described_class.promote_if_healthy!(node)).to eq(false)
+    expect(node.reload.status).to eq("provisioning")
+  end
+end