Fix minimum version CI failures for React 18 compatibility

Two fixes:

1. Skip uncommitted changes check in CI environments
   - CI often makes temporary modifications (e.g., script/convert for minimum
     version testing) before running generators
   - Add CI=true check alongside existing COVERAGE=true check in git_utils.rb
   - Add test coverage for CI environment skip behavior

2. Use react-helmet-async for React 18 minimum version testing
   - @dr.pogodin/react-helmet only supports React 19+
   - react-helmet-async supports React 16-18 and has the same HelmetProvider API
   - script/convert now swaps the package and updates imports for minimum testing

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: justin808

react_on_rails/lib/react_on_rails/git_utils.rb

@@ -5,7 +5,9 @@
 module ReactOnRails
   module GitUtils
     def self.uncommitted_changes?(message_handler, git_installed: true)
-      return false if ENV["COVERAGE"] == "true"
+      # Skip check in CI environments - CI often makes temporary modifications
+      # (e.g., script/convert for minimum version testing) before running generators
+      return false if ENV["CI"] == "true" || ENV["COVERAGE"] == "true"
 
       status = `git status --porcelain`
       return false if git_installed && status&.empty?

react_on_rails/spec/react_on_rails/git_utils_spec.rb

@@ -8,6 +8,14 @@ module ReactOnRails
       context "with uncommitted git changes" do
         let(:message_handler) { instance_double("MessageHandler") } # rubocop:disable RSpec/VerifiedDoubleReference
 
+        around do |example|
+          # Temporarily unset CI env var to test actual uncommitted changes behavior
+          original_ci = ENV.fetch("CI", nil)
+          ENV.delete("CI")
+          example.run
+          ENV["CI"] = original_ci if original_ci
+        end
+
         it "returns true" do
           allow(described_class).to receive(:`).with("git status --porcelain").and_return("M file/path")
           expect(message_handler).to receive(:add_error)
@@ -22,9 +30,37 @@ module ReactOnRails
         end
       end
 
+      context "when CI environment variable is set" do
+        let(:message_handler) { instance_double("MessageHandler") } # rubocop:disable RSpec/VerifiedDoubleReference
+
+        around do |example|
+          original_ci = ENV.fetch("CI", nil)
+          ENV["CI"] = "true"
+          example.run
+          ENV["CI"] = original_ci
+          ENV.delete("CI") unless original_ci
+        end
+
+        it "returns false without checking git status" do
+          # Should not call git status at all
+          expect(described_class).not_to receive(:`)
+          expect(message_handler).not_to receive(:add_error)
+
+          expect(described_class.uncommitted_changes?(message_handler, git_installed: true)).to be(false)
+        end
+      end
+
       context "with clean git status" do
         let(:message_handler) { instance_double("MessageHandler") } # rubocop:disable RSpec/VerifiedDoubleReference
 
+        around do |example|
+          # Temporarily unset CI env var to test actual clean git behavior
+          original_ci = ENV.fetch("CI", nil)
+          ENV.delete("CI")
+          example.run
+          ENV["CI"] = original_ci if original_ci
+        end
+
         it "returns false" do
           allow(described_class).to receive(:`).with("git status --porcelain").and_return("")
           expect(message_handler).not_to receive(:add_error)
@@ -36,6 +72,14 @@ module ReactOnRails
       context "with git not installed" do
         let(:message_handler) { instance_double("MessageHandler") } # rubocop:disable RSpec/VerifiedDoubleReference
 
+        around do |example|
+          # Temporarily unset CI env var to test actual git not installed behavior
+          original_ci = ENV.fetch("CI", nil)
+          ENV.delete("CI")
+          example.run
+          ENV["CI"] = original_ci if original_ci
+        end
+
         it "returns true" do
           allow(described_class).to receive(:`).with("git status --porcelain").and_return(nil)
           expect(message_handler).to receive(:add_error)

script/convert

@@ -47,6 +47,19 @@ gsub_file_content("../package.json", /"react": "[^"]*",/, '"react": "18.0.0",')
 gsub_file_content("../package.json", /"react-dom": "[^"]*",/, '"react-dom": "18.0.0",')
 gsub_file_content("../react_on_rails/spec/dummy/package.json", /"react": "[^"]*",/, '"react": "18.0.0",')
 gsub_file_content("../react_on_rails/spec/dummy/package.json", /"react-dom": "[^"]*",/, '"react-dom": "18.0.0",')
+
+# Switch from @dr.pogodin/react-helmet (React 19+) to react-helmet-async (React 18 compatible)
+# Both have the same HelmetProvider API, but different package names
+gsub_file_content("../react_on_rails/spec/dummy/package.json", /"@dr\.pogodin\/react-helmet": "[^"]*",/, '"react-helmet-async": "^1.3.0",')
+# Update import statements in all client files
+Dir.glob(File.expand_path("../react_on_rails/spec/dummy/client/**/*.{js,jsx,ts,tsx}", __dir__)).each do |file|
+  content = File.binread(file)
+  if content.include?("@dr.pogodin/react-helmet")
+    content.gsub!(%r{from ['"]@dr\.pogodin/react-helmet['"]}, 'from "react-helmet-async"')
+    content.gsub!(%r{['"]@dr\.pogodin/react-helmet['"]}, '"react-helmet-async"')
+    File.binwrite(file, content)
+  end
+end
 gsub_file_content(
   "../packages/react-on-rails-pro/package.json",
   /"test:non-rsc": "(?:\\"|[^"])*",/,