Write & POST June 11 standup to Slack (12:30-13:30 UTC window) — queue-for-N+2 substrate fix

Post the June 11 standup to Carson Slack DM (target D0B0980TR88) in the 12:30-13:30 UTC window. Queue-for-N+2 task: queued by the 2026-06-09 04:10 UTC cron alongside the June 10 standup so a single missed cron cannot again take out a day. Body composed dynamically at lease time based on live state at 12:25 UTC. Mandatory step (0): eval "$(~/bin/gh-fleet-token.sh)" as isolated standalone-line, verify GH_TOKEN length=40 on next line. Mandatory final-refresh step: live gh pr view on all owned PRs; read last 25 Carson DMs. Send-side window guard: no post before 2026-06-11T12:30:00Z. Post-push duplicate-suppression gate. Atomic completion PATCH with slack_ts + memory_file + delivered_at.