Let the header prefix test find the project with its decision count

main's new header test looked up the score disclosure by the exact name
"score". In the shared E2E database, earlier tests leave unanswered
decisions, so with sidebar counts the disclosure is named
"score, N unanswered decisions". Match the optional count suffix, as the
other score disclosure lookups already do.

Refs #345

Assistant-model: Claude Opus 5.5 (fast)
Assistant-workflow: inline
Assistant-verification: Playwright E2E failed in GitHub CI run 37850621091: document-navigation:281 could not find the exact "score" disclosure
Assistant-verification: Playwright E2E passed: smoke and document-navigation with one worker, 51 passed; overlapping-workspace test document-navigation:748 failed once and passed 5/5 on repeat
Co-authored-by: Alex Lavaee <lavaman131@github.com>