fix(entry): the callsign box stops moving when the padlock closes

Its row gains a date field for a manual entry, and a flex row makes room
by shrinking its children — so the widest box, which is the one the eye
is on while typing, was the one that visibly narrowed.

A notch narrower and shrink-0: the size it will always be, with or
without the date, and the slack now comes from the boxes beside it.

frontend/src/App.tsx

@@ -5416,8 +5416,15 @@ export default function App() {
   // "59+30" turned up, which is five characters plus its padding and no longer
   // fitted. The RST fields are back to their original width; the callsign keeps
   // the rest of the row.
+  // shrink-0, and a notch narrower than it used to be.
+  //
+  // The row it sits in gains a date field when the padlock is closed, and a
+  // flex row makes room by shrinking its children — so the callsign box, the
+  // widest of them, visibly narrowed the moment the operator started a manual
+  // entry. The field the eye is on while typing must not move. It is now the
+  // size it will always be, and the slack comes from the boxes beside it.
   const callsignBlock = (
-    <div className="flex flex-col w-56" data-esm="call">
+    <div className="flex flex-col w-52 shrink-0" data-esm="call">
       <Label className="flex items-center gap-2 h-3.5" style={{ marginBottom: 6 }}>
         <span className="text-primary font-semibold">{t('field.callsign')}</span>
         {lookupBusy && (