intake: coverage scan updates the #5875 report, never one ticket per function #5879

Noah 15:37Z item 3 (via aprender-57). The per-function 'test: cover ' tickets (154 filed, rolled into epic #5875) must not come back. Fix: LAB guard check_coverage_single_report.sh (guards-nightly) goes red when an open issue titled 'test: cover ...' exists that is not named in #5875 as 'live PR'; the coverage scan's only issue write is the single tracking issue edit in coverage-nightly.yml. Owner: aprender-w5382.