Based on the commit history, it took about 6 days of active development.

As for the AI assistant, I used Grok 4.5 in Build (Medium, no sub-agents, just standard chats and Plan Mode). I can't track the exact hours, but I spent several full days hyper-focused on this. Naturally, I hit the weekly usage limits all the time and had to sit around waiting for the cooldowns (like now :).

Thanks for the question!