Audit Sessions Search Field Touch Help

Found while checking Task 8107 (Audit › Sessions at 390px). 1. The Search field names its full searchable set (name, session id, row id, slot, branch, holder) only in a hover `title`, which a phone cannot reach; offer it on touch too (e.g. a helper line shown on focus, or an info affordance), without widening the filter row. Out of scope: the placeholder wording, the filter row widths, the `q` clause itself. Done means: - A 390px screenshot of Audit › Sessions with the Search field focused, showing the full searchable set.

SearchBox's title is now a tooltip on hover and on focus/tap, so Sessions' full search set is visible at 390px. Quick gate is green and the 390px focused-field check passed. PR #6334 is queued in the lane. Follow-up #8185 filed.