The vertical half of click-to-insert: resolve a world point to the staff
under the cursor and the natural diatonic pitch at that height under the
staff's clef.
Staff selection is manifestation-aware. Each rendered bottom staff line
carries its staff's manifestation id as the stroke's stable_id, so a click
maps back to a concrete (region, staff_instance) by matching that id, then
chooses the nearest staff by 2D proximity — horizontal span first (which
region, since one staff tiles across regions that can share a y band), then
the vertical band. The earlier StaffId-collapsing helpers are gone.
The clef is resolved by time, not vector order: render_score builds a
per-staff start-clef table from the logical layout via active_clef (now
exported from epiphany-layout-ir) and threads it through open/commit, so a
mid-vector [bass@1, treble@0] still spells the staff start as treble.
A non-finite click is rejected up front — NaN would slip through
dist_to_band's comparisons as distance 0 and saturate the round() as i32
step into a bogus pitch.
Tests cover finite resolution, x-aware manifestation selection across staves
sharing a y band, non-finite rejection, and time-ordered clef resolution.
The GUI surfaces the resolved pitch on an empty-staff click.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NAtEiJtt9yKVV1zjKYmZhS
Levi Neuwirth
8bffd2f2fd