Audit details on framework cards, with clearable dates

Audit details show as pills on the framework card. Auditor name, audit period, and audit engagement date now appear as separate pills on each framework card header, so audit status is readable without opening the framework. A framework with none of them set shows a single "Audit details not set" pill.

Clear a date you no longer need. Edit audit details now includes a Clear all dates action, plus a clear control on each filled date picker, so a date entered by mistake can be removed instead of worked around. Clearing dates leaves the auditor name in place.