feat(ui): mouthfeel chips in the studios/tools + clean up the chip pickers

[rvnminers-A-and-N]

Add mouthfeel as a first-class selectable dimension in the formulation/flavor studios — its own chip row (cooling / pungent / warming / astringent / tingling), alongside flavors and notes. AND do a real usability pass on the whole chip UX: it's only intuitive if you built it. Group/label the pickers clearly (Flavors / Notes(aroma) / Mouthfeel / Taste), searchable, with counts, and consistent chip styling. Ties #214 #229 #50 #232.

[rvnminers-A-and-N]

Mouthfeel chips shipped in #245 — both pickers now have a Mouthfeel group, and verification on the live box caught two real bugs (empty tingling/astringent chips, and pungent returning sharp-smelling molecules instead of the TRPV1 burn; mouthfeel terms are now namespaced). Leaving this open for the remaining half: the broader chip-picker usability pass.

[rvnminers-A-and-N]

Complete. Mouthfeel is a selectable dimension in both studios (#245); the 178-note flat wall is now 15 perceptual families with counts plus one filter across all chips (#246, which also closed #223); and the head-coverage audit in #248 found three trained taste heads (sour, salty, tasteless) that the picker silently omitted — all 187 heads now have a role, with the 12 Tox21 heads surfaced as a filter + per-result flags rather than as design targets.