chore(scorecard): align schedule to canonical weekly ('23 4 * * 1') (#20)

Cut 2 of the GH Actions budget rebalancing plan (2026-05-27).
Aligns with standards canonical at hyperpolymath/standards/.github/workflows/scorecard.yml
and standards#230 (reusable example fix).

Estate audit found 180 repos on daily schedule vs 29 on canonical
weekly — this PR converts one of them. Tracking issue: standards#231.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath