No fresh-attack articulation on the receiving note of a tie

A tie represents one sustained sound with a single attack; the destination note of a tie has no re-attack, so it cannot carry staccato/accent/tenuto/marcato (which all describe how a note is attacked or detached). A fermata IS allowed on a tie's final note, since it marks how long the sound is held, not how it is attacked.

Note N has `tie: true` and pitch-matches note N+1, and note N+1 itself carries `articulation: 'accent'` — there is no second attack for the accent to describe.

Gould, Behind Bars, ch. Articulation and ch. Ties — articulation marks apply at the point of attack; Ross, The Art of Music Engraving, is explicit that a tied note is not re-articulated.

This rule can be decided from pitches, durations and voices — no layout required. A validator can check it before anything is drawn.