Improve submenu handling and linkless fixture parsing

[adrunkhuman]

Summary

• fix submenu navigation regressions found in review, including regional cups discovery, mixed drillable fixture selection, and stale async submenu errors
• harden linkless fixture parsing by handling rows with extra score-like metadata and add a saved HTML fixture covering the ambiguous case
• expand site and UI regression coverage for archive menus, regional associations, and linkless fixture navigation