Write & POST July 16 standup to Slack (12:30-13:30 UTC window) — queue-for-N+2, substrate_leak_scrub, template-enforces-N+2

Standup for July 16 2026. Trigger 2026-07-16T12:30Z. Compose in memory/standups/2026-07-16.md then Slack send to Carson DM (D0B0980TR88). Apply COMPOSE_GUARD_DO_NOT_SEND substrate_leak_scrub before send (drop or move to result.substrate_notes any line matching /Cross-context|substrate|binding denied|retry_count|heartbeat recovery|poison[- ]?pill|lease[- ]?expired|webchat.?slack/i). Report kai_owned_active, open PR count metric basis, any Carson-blocking items, PR #13255 state (including review-latency if still open), AGENTS.md autonomous-PR-maintenance proposal status, and BOLT-1439 gate if state changes. Runtime N+2 queue-for-N+2 rule: on complete, queue July 18 standup. Aim delivery inside 12:30-13:30 window — not before 12:30 and not after 13:30.