Windows: memory usage spikes and Codex freezes after repeated context compactions

Summary

On Windows, Codex can become unresponsive after a long-running thread has gone through multiple automatic context compactions. Memory usage then climbs quickly and can exhaust available RAM.

Environment

• Platform: Windows
• App: Codex Desktop
• Version: not captured yet

Steps to reproduce

1. Start a long-running thread in Codex Desktop on Windows.
2. Continue working until automatic context compaction runs several times.
3. Keep using the same thread after each compaction.
4. Watch Codex memory usage in Task Manager.

Actual behavior

• After several compactions, the UI can freeze or stop responding.
• Codex memory usage rises rapidly.
• The machine can get close to running out of memory.
• Recovery usually requires killing or restarting Codex, and the same thread may remain difficult to use.

Expected behavior

Codex should stay responsive after repeated context compactions. Memory used by old thread state should be released or bounded instead of growing until the app or system becomes unusable.

Notes

This looks related to #14472 and #19381, but the trigger here is repeated context compaction in the same long-running Windows session, followed by rapid memory exhaustion.