Durable Object alarm loop: $34k in 8 days, zero users, no platform warning

Description

Sharing this as a warning to anyone using Cloudflare Durable Objects with alarms. Root cause: My DO agent's onStart() handler called this.ctx.storage.setAlarm() on every wake-up without checking whether an alarm was already scheduled. Combined with 60+ preview Worker deployments each creating independent DO instances, this created a runaway self-health-check loop. Timeline: - April 3: loop began (zero DO usage before this date) - April 4-5: peaked at ~930 billion row reads/day