watch: scan the marketplace daily (was weekly)

[askalf]

Flips marketplace-watch from weekly (Mondays 06:17) to daily (06:17). Cuts worst-case poison-detection latency 7d→1d for the live board at https://truecopy.askalf.org; cheap (public repo, deterministic scan), matches the existing daily npm-drift-watch. Comment/header wording updated to match. Site copy flips weekly→daily once this merges.

🤖 Generated with Claude Code

[sprayberry-reviewer]

Automated review from the Sprayberry Labs fleet code reviewer.

Verdict: Clean — no blocking issues found. Approving.

What I checked

• gh pr diff 79 — the entire change is a 2-line workflow edit in .github/workflows/marketplace-watch.yml: the cron schedule flips from weekly (17 6 * * 1, Mondays) to daily (17 6 * * *), plus the matching comment/inline-comment text update ("weekly" → "daily").
• Cron field arithmetic: 17 6 * * * is a valid 5-field cron expression meaning "06:17 UTC every day" — correct for the stated intent, and the minute offset (:17) still staggers it off the top-of-hour grid as the updated inline comment claims.
• CI check-rollup (statusCheckRollup): all 9 checks green — test matrix (ubuntu/windows/macos × node 20/22), CodeQL analyze, and the repo's own "verify pinned skills" gate all report SUCCESS.
• No code paths, permissions, or trigger conditions besides the cron string change — workflow_dispatch: {} and permissions: blocks are untouched.

What's good

• Minimal, single-purpose diff exactly matching the PR description (weekly → daily latency reduction for a deterministic, low-cost scan).
• Comment text was kept in sync with the behavior change (no stale "weekly" reference left behind).
• All CI signals green before review.

No correctness, security, reuse, or test-coverage concerns in the changed lines — nothing to request changes on.