Vouch request: fix for #4286 #4287

Why do you want to contribute?

I'd like to fix #4286, which I hit and reported today: starting a second trigger dev session can crash it or silently break rebuilds, because the old session's exit cleanup deletes the tmp store both sessions share. The issue includes the root cause in the CLI source and a one-line fix I've already verified locally; the PR would add that mkdir in createFileWithStore plus a regression test beside the existing utilities tests. I run around 20 production Trigger.dev tasks day to day and I'm currently building a product on chat.agent, so I expect to keep contributing as I go deeper.

Prior contributions or relevant experience

https://github.com/mcheemaa/mistri (an agent harness for Ruby I build and maintain: model loop, streaming, durable sessions, MCP)
https://github.com/ghostwright/ghost-os (open-source macOS computer use for AI agents)
https://github.com/ghostwright/phantom (an AI co-worker platform on the Claude Agent SDK)