fix: move wait command outside loop in generate_commands_rec for proper parallel execution

[Galoretka]

Fix logical error where wait was executed immediately after each background
process in the for loop, making parallel execution ineffective.

• Moved wait command from inside the loop to the end of generate_commands_rec function
• Now all recursive calls run in parallel and wait for completion at the end
• Improves performance by allowing concurrent subcommand processing