Billing upgrade/downgrade, inviti in app e diretta YouTube da mobile.

Upgrade Stripe con addebito immediato; downgrade programmato a fine periodo.
UX billing più sobria con box info; icone piani. API inviti e OAuth YouTube
per staff trasmissione; deep link join; scelta partita programmata o nuova.

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

backend/spec/requests/api/v1/invitations_spec.rb

@@ -0,0 +1,54 @@
+require "rails_helper"
+
+RSpec.describe "Api::V1::Invitations", type: :request do
+  let(:club) { Club.create!(name: "FC Test", sport: "volleyball", primary_color: "#e53935", secondary_color: "#ffffff") }
+  let(:team) { club.teams.create!(name: "Squadra A", sport: "volleyball") }
+  let(:owner) do
+    User.create!(email: "owner@test.it", name: "Owner", password: "password123", role: "coach").tap do |u|
+      ClubMembership.create!(user: u, club: club, role: "owner")
+    end
+  end
+  let(:invitee) { User.create!(email: "streamer@test.it", name: "Streamer", password: "password123", role: "coach") }
+  let(:token) { TeamInvitation.generate_token }
+  let!(:invitation) do
+    team.team_invitations.create!(
+      email: invitee.email,
+      token_digest: Digest::SHA256.hexdigest(token),
+      role: "member",
+      staff_kind: "transmission",
+      expires_at: 7.days.from_now
+    )
+  end
+
+  describe "GET /api/v1/invitations/:token" do
+    it "mostra anteprima invito valido" do
+      get "/api/v1/invitations/#{token}"
+      expect(response).to have_http_status(:ok)
+      expect(response.parsed_body["email"]).to eq("streamer@test.it")
+      expect(response.parsed_body["team_name"]).to eq("Squadra A")
+    end
+  end
+
+  describe "POST /api/v1/invitations/:token/accept" do
+    it "accetta con email corretta" do
+      post "/api/v1/auth/login", params: { email: invitee.email, password: "password123" }
+      access = response.parsed_body["access_token"]
+
+      post "/api/v1/invitations/#{token}/accept",
+           headers: { "Authorization" => "Bearer #{access}" }
+
+      expect(response).to have_http_status(:ok)
+      expect(invitee.user_teams.find_by(team: team)&.staff_kind).to eq("transmission")
+    end
+
+    it "rifiuta email diversa" do
+      post "/api/v1/auth/login", params: { email: owner.email, password: "password123" }
+      access = response.parsed_body["access_token"]
+
+      post "/api/v1/invitations/#{token}/accept",
+           headers: { "Authorization" => "Bearer #{access}" }
+
+      expect(response).to have_http_status(:unprocessable_entity)
+    end
+  end
+end