v0.6.23

feat: Debug aggregate shows one row per Instance

The aggregated Debug view coalesced by (PGN, source), so a PGN reporting several
Instances from one source (e.g. several engines) collapsed into a single row
whose values jumped between instances. Key the rows by instance too (when the
frame carries an integer Instance) and add an Inst column; PGNs without an
Instance field are unchanged. The instance helper now lives in decode.canboat
(frame_instance) and is shared by the Auto page and this view.

Bumps to 0.6.23.