fix(review): thickness band derived from thickness_in (#88); MultiSelect shows selected names + commits on toggle settle (#90)

#88 — thickness band is now display-only, derived deterministically from
thickness_in against the synced Woo thickness terms (TV-9 / QUALITY-95).
Replaces the <select> with a read-only div. New pure function
deriveThicknessTermId + 6 unit tests. Docs (UAT-PRACTICE, contracts/UX)
updated to reflect the band is not an owner control.

#90 — MultiSelect closed state now shows the selected option names
(truncated to 2 + +N) instead of just a count. onCommit prop wired so
multi-select changes persist + re-review immediately (250ms debounce,
flush on Done, cleanup on destroy). Single-select binds use string vars
(speciesSel/edgeSel/gradeSel) to fix the number/string mismatch with
<option value={id}>; a tick()-deferred syncSelects() keeps the DOM
option in sync after programmatic writes (AI prefill, reload hydrate)
that Svelte's own select_option would otherwise reset.

docs/contracts/UX.md

@@ -55,8 +55,11 @@ Cites REVIEW-5, REVIEW-15, REVIEW-20, METADATA-45.
   with an "AI" badge; below it the field starts empty. The badge is presentation only and clears
   on edit.
 - **Required set.** Exactly one species and at least one wood-category leaf; one Edge Type, at
-  least one Figure, exactly one Grade, one Thickness band, one Moisture; fig-* and feat-* tags
-  optional; price; title, short_description, and description.
+  least one Figure, exactly one Grade, one Moisture; fig-* and feat-* tags optional; price;
+  title, short_description, and description. The **Thickness band is not an owner control** — it
+  is derived deterministically from `thickness_in` (the value rounds up into the synced Woo band,
+  `TV-9` / `QUALITY-95`), displayed read-only, and satisfies the readiness requirement
+  (`REVIEW-5`) via that derived value.
 - **Primary category.** The owner declares one primary wood category and any secondary ones; the
   default is the first selected.
 - **Inline nudges.** Every empty required field shows an inline nudge as the owner works; there is