[Feature Request] Add cost limit configuration to prevent unattended runs from exceeding budget

Bug Description
I would like to clamp usage costs for long runs to a dollar amount so claude doesn't spin out of control when it's unattended.

I sometimes setup long runs overnight, then go to bed. I'm worried that I will wake up to a $500 million dollar bill from Anthropic. So I tell claude to keep costs below $500 for example.

However, it would be nice to be able to SET the upper limit for a session to some dolar amount.
You already track /usage. Let me set a clamp so that if /usage hits a dollar amount it stops and shows an error to me that it reached the clamp.
Then I can either clear it or start a new session.

Environment Info

• Platform: win32
• Terminal: windows-terminal
• Version: 2.1.168
• Feedback ID: 7fb73969-eda0-4bc2-84b9-be57926ec8f7

Errors

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