docs(ui): quote the shipped fade's own measurement

The comment on `wa-dialog::part(body)` carried bottom-edge pixels from
an intermediate probe (29,33,36) while `.planning/NOTES.md` recorded
the final sample against the shipped rule (22,24,27) — the same
gradient, read a few pixels higher up the box. A measurement written in
two places has to agree, or neither can be trusted.

frontend/src/components/menu-surface/menu-surface.ts

@@ -184,8 +184,10 @@ export class MenuSurface extends LitElement {
            its label centred, so 32px of scrim that is already down to
            a quarter strength at 14px reaches y-centre at about 0.06 and
            spends its weight on the strip below the last legible label.
-           Measured on the dark ramp: 52,58,64 flat before, 52,57,63 at
+           Measured on the dark ramp at x=300, flat 52,58,64 throughout
-           the label and 29,33,36 at the bottom edge after. */
+           before: 50,56,62 at y=330, 33,37,40 at y=350 and 22,24,27 at
+           the bottom edge, and flat again at the end of the list. The
+           light ramp puts 9.9:1 on the last label. */
         wa-dialog::part(body) {
             padding: 0;
             overflow-y: auto;