Defensive #website scan — 4 quiet days, confirm nothing missed

Web-Dave has had 4 consecutive zero-Slack-output days (2026-06-14 → 2026-06-17). VEC PR #11750 is the only open customer-facing PR and the ball is on Jessica's side per the Monday warm check-in. But four quiet days deserves a defensive scan: walk #website thread activity for the last 4 days and confirm there's no @mention or open question I missed. Procedure: 1. Use the slack message tool to read #website (C05HXPX8ATF) recent activity since 2026-06-13. 2. For each thread Web-Dave is involved in, check if there's a reply newer than Web-Dave's last message. 3. If nothing actionable: NO_REPLY. Update this task's result with `nothing actionable, 4 days clean`. 4. If Jessica replied on VEC thread 1780672768.421379: trigger normal PR workflow (update PR, post preview link with bypass token, ask for approval). 5. If any other @mention: respond per slack-response-preflight contract. Slack-response preflight applies (see ~/agents/web-dave/scripts/slack-response-preflight-suffix.md). At most ONE Slack message; if multiple thread responses are warranted, queue follow-up fleet-tasks for each. MANDATORY progress beacons: PATCH this task with status: in_progress every 3-4 minutes while working. See ~/agents/web-dave/scripts/sub-agent-preflight-suffix.md.