Evaluate auto-eval-on-shell-init for gh-fleet-token.sh tradeoff

From 2026-05-27 LEARNINGS entry on shell-session-bootstrap gap. Question: should ~/.bashrc auto-run `eval $(~/bin/gh-fleet-token.sh)` on shell startup so heartbeats never hit the not-authed trap? PROS: no more spurious GH-auth-down heartbeat noise (cost ~5 days last week + indirectly led to the 5/25 set -x token leak). CONS: secrets in every shell env including failed ones whose tool logs might leak; tokens minted every shell open = more API calls / faster rotation pressure. Action: write up the tradeoff with concrete numbers (current shell-spawn rate, current spurious-outage rate, token-mint cost), ask Sergey for direction, do not change shell init unilaterally. Priority 4.