Add UI smoke test for search and playback on basic-auth Invidious

Exercises the read path end-to-end against an Invidious instance fronted
by an HTTP Basic Auth reverse proxy: adds the instance via the new
basic-auth-aware add helper, navigates to Search, runs a query, taps the
first result, waits for the player to expand and start playback, then
closes the player. Confirms that ContentService's per-instance HTTPClient
(with the basic-auth Authorization header baked in via setDefaultHeaders)
is wired correctly through search, video metadata fetch, and stream
loading.

Skips cleanly when INVIDIOUS_BASIC_AUTH_USERNAME / _PASSWORD are not set.

spec/ui/smoke/invidious_basic_auth_search_play_spec.rb

@@ -0,0 +1,74 @@
+# frozen_string_literal: true
+
+require_relative '../spec_helper'
+
+RSpec.describe 'Search and play on basic-auth Invidious', :smoke do
+  before(:all) do
+    skip 'INVIDIOUS_BASIC_AUTH_USERNAME / _PASSWORD not set' unless UITest::Config.invidious_basic_auth_credentials?
+
+    # Boot simulator
+    @udid = UITest::Simulator.boot(UITest::Config.device)
+
+    # Build app (unless skipped)
+    UITest::App.build(
+      device: UITest::Config.device,
+      skip: UITest::Config.skip_build?
+    )
+
+    # Install and launch
+    UITest::App.install(udid: @udid)
+    UITest::App.launch(udid: @udid)
+
+    # Wait for app to stabilize
+    sleep UITest::Config.app_launch_wait
+
+    # Initialize helpers
+    @axe = UITest::Axe.new(@udid)
+    @instance_setup = UITest::InstanceSetup.new(@axe)
+    @search_helper = UITest::SearchHelper.new(@axe)
+    @player_helper = UITest::PlayerHelper.new(@axe)
+
+    # Make the basic-auth Invidious instance the only Invidious-compatible source
+    # so search and playback route through the reverse proxy.
+    @instance_setup.remove_yattee_server(UITest::Config.yattee_server_host)
+    @instance_setup.remove_and_add_invidious_with_basic_auth(
+      UITest::Config.invidious_basic_auth_url,
+      username: UITest::Config.invidious_basic_auth_username,
+      password: UITest::Config.invidious_basic_auth_password
+    )
+  end
+
+  after(:all) do
+    UITest::App.terminate(udid: @udid, silent: true) if @udid
+    UITest::Simulator.shutdown(@udid) if @udid && !UITest::Config.keep_simulator?
+  end
+
+  describe 'searching and playing a video through the basic-auth proxy' do
+    it 'searches, taps a video, plays it, and closes the player' do
+      video_id = 'XfELJU1mRMg'
+
+      # Navigate to Search and run a query for the known video
+      @search_helper.navigate_to_search
+      expect(@search_helper.search_visible?).to be true
+
+      @search_helper.search(video_id)
+      @search_helper.wait_for_results
+
+      expect(@search_helper.results_visible?).to be true
+
+      # Tap the first result thumbnail to start playback directly
+      @search_helper.tap_first_result_thumbnail
+
+      # Wait for the player to expand and start playback
+      @player_helper.wait_for_player_expanded
+      @player_helper.wait_for_playback_started
+
+      @axe.screenshot('invidious_basic_auth_playback_playing')
+
+      # Close the player
+      @player_helper.close_player
+
+      @axe.screenshot('invidious_basic_auth_playback_after_close')
+    end
+  end
+end