Logging in from a second browser ended the first one's session at its next
request: two browsers open on the switch logged each other out every few
seconds. Up to four sessions now, each with its own cookie and expiry; a
fifth login replaces the least recently used. The expiry check is a leaf
function so its 32-bit scratch stays out of internal RAM (stack still
159 bytes with HEALTH).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Tx2W7xVecMoKbBCkD2i8PG
(cherry picked from commit 03330f4077ef8872d861d951c8e44ece3c573935)
