Add timeout and KILL fallback to server shutdown

- Add 10-second timeout to Process.wait to prevent indefinite hangs
- Send KILL signal if server doesn't respond to TERM within timeout
- Prevents test runs from hanging if server doesn't shut down gracefully
- Logs warning when escalating from TERM to KILL

This ensures robust cleanup even when servers are unresponsive to
graceful shutdown signals.

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

Co-Authored-By: Claude <noreply@anthropic.com>

Author: justin808

lib/cypress_on_rails/server.rb

@@ -155,7 +155,16 @@ def stop_server(pid)
 
       puts "Stopping Rails server (PID: #{pid})"
       send_term_signal(pid)
-      Process.wait(pid)
+
+      begin
+        Timeout.timeout(10) do
+          Process.wait(pid)
+        end
+      rescue Timeout::Error
+        CypressOnRails.configuration.logger.warn("Server did not terminate after TERM signal, sending KILL")
+        safe_kill_process('KILL', pid)
+        Process.wait(pid) rescue Errno::ESRCH
+      end
     rescue Errno::ESRCH
       # Process already terminated
     end