Flow Debugger's script-entry instance selection and Debug View's instance
selection both go through the shared InstancePicker combobox now instead of
a flat <select>. Update the tests to type into the {prefix}-input, wait for
the matching {prefix}-row, and click it; keep the <select>-polling helper
for the site select, which is unchanged.
Claude-Session: https://claude.ai/code/session_01NcMG6xXdsJbmD2wYAgkK29
Joseph Doherty
07c5d53f39