refactor: inline restore_git_revision into checkout_vcs

Single method, no delegation. The SVN branch is gone so checkout_vcs
no longer needs to dispatch. Updated 3 callers.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: pftg

lib/capybara/screenshot/diff/vcs.rb

@@ -6,13 +6,9 @@ module Capybara
   module Screenshot
     module Diff
       module Vcs
-        def self.checkout_vcs(root, screenshot_path, checkout_path)
-          restore_git_revision(screenshot_path, checkout_path, root: root)
-        end
-
         SILENCE_ERRORS = Os::ON_WINDOWS ? "2>nul" : "2>/dev/null"
 
-        def self.restore_git_revision(screenshot_path, checkout_path = screenshot_path, root:)
+        def self.checkout_vcs(root, screenshot_path, checkout_path)
           vcs_file_path = screenshot_path.relative_path_from(root)
           redirect_target = "#{checkout_path} #{SILENCE_ERRORS}"
           show_command = "git show HEAD~0:./#{vcs_file_path}"

test/system_test_case.rb

@@ -65,7 +65,7 @@ def rollback_comparison_runtime_files(screenshot_assert)
     save_annotations_for_debug(comparison)
 
     screenshot_path = comparison.image_path
-    Vcs.restore_git_revision(screenshot_path, root: Capybara::Screenshot.root)
+    Vcs.checkout_vcs(Capybara::Screenshot.root, screenshot_path, screenshot_path)
 
     if comparison.difference
       comparison.reporter.clean_tmp_files

test/unit/vcs_test.rb

@@ -19,11 +19,11 @@ class VcsTest < ActiveSupport::TestCase
           end
         end
 
-        test "#restore_git_revision checks out and verifies the original screenshot" do
+        test "#checkout_vcs checks out and verifies the original screenshot" do
           screenshot_path = file_fixture("images/a.png")
 
           base_screenshot_path = Pathname.new(@base_screenshot.path)
-          assert Vcs.restore_git_revision(screenshot_path, base_screenshot_path, root: Screenshot.root)
+          assert Vcs.checkout_vcs(Screenshot.root, screenshot_path, base_screenshot_path)
 
           assert base_screenshot_path.exist?
           assert_equal screenshot_path.size, base_screenshot_path.size