Fix ProcessManager test stubbing for system calls

The tests were expecting system() to be called with a single string,
but the implementation correctly uses array arguments for security.
Updated tests to match the implementation.

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

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

Author: justin808

spec/react_on_rails/dev/pack_generator_spec.rb

@@ -32,6 +32,9 @@
       command = "bundle exec rake react_on_rails:generate_packs > /dev/null 2>&1"
       allow_any_instance_of(Object).to receive(:system).with(command).and_return(false)
 
+      # Suppress the puts output
+      allow_any_instance_of(Object).to receive(:puts)
+
       expect { described_class.generate(verbose: false) }.to raise_error(SystemExit)
     end
   end

spec/react_on_rails/dev/process_manager_spec.rb

@@ -46,19 +46,20 @@
     before do
       allow(ReactOnRails::Dev::FileManager).to receive(:cleanup_stale_files)
       allow_any_instance_of(Kernel).to receive(:system).and_return(true)
+      allow(File).to receive(:readable?).and_return(true)
     end
 
     it "uses overmind when available" do
       allow(described_class).to receive(:installed?).with("overmind").and_return(true)
-      expect_any_instance_of(Kernel).to receive(:system).with("overmind start -f Procfile.dev")
+      expect_any_instance_of(Kernel).to receive(:system).with("overmind", "start", "-f", "Procfile.dev")
 
       described_class.run_with_process_manager("Procfile.dev")
     end
 
     it "uses foreman when overmind not available" do
       allow(described_class).to receive(:installed?).with("overmind").and_return(false)
       allow(described_class).to receive(:installed?).with("foreman").and_return(true)
-      expect_any_instance_of(Kernel).to receive(:system).with("foreman start -f Procfile.dev")
+      expect_any_instance_of(Kernel).to receive(:system).with("foreman", "start", "-f", "Procfile.dev")
 
       described_class.run_with_process_manager("Procfile.dev")
     end