Add max session length/turns limit

[alexknowshtml]

Summary

Limit how long Claude sessions can run or how many turns they can take to prevent runaway costs.

Implementation Options

1. Max turns - Count messages in a thread, stop responding after N turns
2. Max duration - Track session start time, stop after X minutes
3. Token budget - Track approximate token usage (harder to implement)

Suggested Behavior

• MAX_TURNS_PER_SESSION=50 - After 50 back-and-forth messages, warn then stop
• MAX_SESSION_DURATION_MS=3600000 - 1 hour max
• Send warning message before hitting limit

Priority

Lower - Claude Code already has its own context limits, this is a secondary safeguard

Related

• Independent of other safety features