Fix DEFAULT_ROUTE for --rsc installs using gsub_file instead of .tt template

The previous approach renamed bin/dev to bin/dev.tt to make DEFAULT_ROUTE
dynamic via ERB. This broke the dummy app (which exec's bin/dev directly)
and the dev_spec.rb tests (which read/load the file from source).

Instead, keep bin/dev as a plain Ruby file and use gsub_file after copying
to change DEFAULT_ROUTE from "hello_world" to "hello_server" when --rsc
is used without --redux (the only case where hello_world doesn't exist).

Co-Authored-By: Claude Opus 4.6 <[email protected]>

Author: ihabadham

react_on_rails/lib/generators/react_on_rails/install_generator.rb

@@ -225,6 +225,11 @@ def add_bin_scripts
         template_bin_path = "#{__dir__}/templates/base/base/bin"
         directory template_bin_path, "bin"
 
+        # For --rsc without --redux, hello_world doesn't exist — update DEFAULT_ROUTE
+        if use_rsc? && !options.redux?
+          gsub_file "bin/dev", 'DEFAULT_ROUTE = "hello_world"', 'DEFAULT_ROUTE = "hello_server"'
+        end
+
         # Make these and only these files executable
         files_to_copy = []
         Dir.chdir(template_bin_path) do

react_on_rails/spec/react_on_rails/generators/install_generator_spec.rb

@@ -13,6 +13,12 @@
     include_examples "base_generator", application_js: true
     include_examples "no_redux_generator"
 
+    it "sets DEFAULT_ROUTE to hello_world in bin/dev" do
+      assert_file "bin/dev" do |content|
+        expect(content).to include('DEFAULT_ROUTE = "hello_world"')
+      end
+    end
+
     it "installs appropriate transpiler dependencies based on Shakapacker version" do
       assert_file "package.json" do |content|
         package_json = JSON.parse(content)
@@ -743,6 +749,12 @@
         expect(content).to include("rsc_payload")
       end
     end
+
+    it "sets DEFAULT_ROUTE to hello_server in bin/dev" do
+      assert_file "bin/dev" do |content|
+        expect(content).to include('DEFAULT_ROUTE = "hello_server"')
+      end
+    end
   end
 
   context "with --rsc --redux" do