$60K Billed in 13 Hours: Why Leaked Firebase Keys Keep Killing AI-Built Apps

A Japanese dev just got billed roughly $60,000 (~9 million yen) in 13 hours because a Google API key leaked from their Firebase + Gemini app. I saw the post trending on Qiita this morning and my stomach dropped — not because it's a new story, but because I've seen the exact same mistake every single