Write & POST July 13 standup to Slack (12:30-13:30 UTC window) — queue-for-N+2, substrate_leak_scrub, window_discipline_note, template_enforces_n_plus_2

Compose July 13 standup covering: PR #13255 review/merge state; AGENTS.md proposal day 6 pending; window discipline N=5 test; direct-ask-starvation counter shipped result (PR #13255 opened via no-objection default). Post to Slack DM to Carson inside 12:30-13:30 UTC window. Write memory/standups/2026-07-13.md. Cold-start standup because reflection audit found only July 14 queued (N+2 gap detected at July 13 04:10Z cron).