Keep the keyboard on the grid after the formula bar; editor uses cell colours

- Enter/Escape in the formula bar (and a jump via the Name Box) hand the
  focus back to the table of the selection, so the arrow keys move the
  active cell again instead of doing nothing.
- The in-cell editor takes the cell's own text/fill colour and bold/
  italic, so a light-on-dark cell no longer turns into dark text on a
  dark fill while editing.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/frontend/components/TableGrid.vue

@@ -878,12 +878,21 @@ let committing = false;
 const editStyle = computed(() => {
   const s = editing.value;
   if (!s) return {};
-  return {
+  // look like the cell being edited: its own text/fill colour (else the
+  // table's), bold/italic -- a white-on-dark cell must not turn into dark
+  // text on a dark fill while editing
+  const f = store.cellFormat(props.tableId, s.col, s.row);
+  const style: Record<string, string> = {
     left: colLeft(s.col) + 'px',
     top: rowTop(s.row) + 'px',
     minWidth: colWidth(s.col) + 'px',
     minHeight: rowH(s.row) + 'px',
   };
+  if (f.color) style['--text'] = f.color;
+  if (f.bg) style['--surface'] = f.bg;
+  if (f.bold) style.fontWeight = '600';
+  if (f.italic) style.fontStyle = 'italic';
+  return style;
 });
 const editMirrorStyle = computed(() => {
   const s = editing.value;
@@ -1332,7 +1341,14 @@ const totalWidth = computed(() => {
   return w;
 });
 
+// the formula bar / Name Box hand the keyboard back after Enter/Escape
+function onFocusGridRequest(e: Event) {
+  if ((e as CustomEvent<string>).detail === props.tableId) root.value?.focus();
+}
+window.addEventListener('numolus:focus-grid', onFocusGridRequest);
+
 onBeforeUnmount(() => {
+  window.removeEventListener('numolus:focus-grid', onFocusGridRequest);
   onDragUp();
   onPointDragUp();
   onFillDragUp();