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.

frontend/src/create/review/thicknessBand.test.ts

@@ -0,0 +1,57 @@
+import assert from 'node:assert/strict';
+import { test } from 'node:test';
+import { deriveThicknessTermId, type ThicknessBand } from './thicknessBand';
+
+// Synced-Woo-shaped bands (id + name). The e2e fixture uses a single "2-4 in" band.
+const BANDS: ThicknessBand[] = [
+  { id: 39, name: '2-4 in' },
+];
+
+test('TV-9 / QUALITY-95: 1 in rounds up into the enclosing synced band', () => {
+  const bands: ThicknessBand[] = [
+    { id: 10, name: '1-2 in' },
+    { id: 39, name: '2-4 in' },
+  ];
+  assert.equal(deriveThicknessTermId(1, bands), 10);
+  assert.equal(deriveThicknessTermId(1.5, bands), 10);
+  // 2.0 is exactly the upper bound of the 1-2 band → belongs to it.
+  assert.equal(deriveThicknessTermId(2.0, bands), 10);
+  // 2.01 falls into 2-4.
+  assert.equal(deriveThicknessTermId(2.25, bands), 39);
+  assert.equal(deriveThicknessTermId(4, bands), 39);
+});
+
+test('e2e fixture: thickness_in 2 → the single "2-4 in" band (id 39)', () => {
+  assert.equal(deriveThicknessTermId(2, BANDS), 39);
+});
+
+test('above every band → empty (no invented band; upstream thickness fix resolves it)', () => {
+  assert.equal(deriveThicknessTermId(5, BANDS), '');
+});
+
+test('no thickness / non-finite → empty', () => {
+  assert.equal(deriveThicknessTermId(null, BANDS), '');
+  assert.equal(deriveThicknessTermId(undefined, BANDS), '');
+  assert.equal(deriveThicknessTermId(0, BANDS), '');
+  assert.equal(deriveThicknessTermId(NaN, BANDS), '');
+  assert.equal(deriveThicknessTermId(2, []), '');
+});
+
+test('band names are parsed from the synced names, never hardcoded (order-independent)', () => {
+  // Reverse the array: the derivation must still pick the right band by bound.
+  const bands: ThicknessBand[] = [
+    { id: 39, name: '2-4 in' },
+    { id: 10, name: '1-2 in' },
+  ];
+  assert.equal(deriveThicknessTermId(1.5, bands), 10);
+  assert.equal(deriveThicknessTermId(3, bands), 39);
+});
+
+test('malformed band names are skipped without throwing', () => {
+  const bands: ThicknessBand[] = [
+    { id: 1, name: 'N/A' },
+    { id: 2, name: '4-2 in' }, // inverted, unusable
+    { id: 39, name: '2-4 in' },
+  ];
+  assert.equal(deriveThicknessTermId(3, bands), 39);
+});