feat: add ARIA labels to inline action buttons in ConfigTable

Added `aria-label` and `title` attributes to the Check, X, and Pencil icon buttons
in ConfigTable.tsx to improve screen reader accessibility and provide
helpful tooltips for sighted users. Also recorded a journal entry in
.Jules/palette.md about the importance of labeling icon-only inline actions.

Co-authored-by: jmbish04 <26469722+jmbish04@users.noreply.github.com>

Author: google-labs-jules[bot]

.Jules/palette.md

@@ -0,0 +1,3 @@
+## 2024-05-21 - Accessible Inline Data Table Actions
+**Learning:** Icon-only buttons used for inline row actions in data tables (like edit, save, cancel) are completely invisible to screen readers without ARIA labels, and confusing to sighted users without tooltips. This is especially problematic in dense tables where context isn't obvious.
+**Action:** Always ensure any icon-only button, regardless of its placement inside complex components like tables, includes both an `aria-label` and `title` attribute explaining its function.

src/frontend/src/components/config/ConfigTable.tsx

@@ -132,15 +132,15 @@ export function ConfigTable({ data, fields, onSave }: ConfigTableProps) {
                 <TableCell className="text-right">
                   {isEditing ? (
                     <div className="flex justify-end gap-2">
-                      <Button size="icon" variant="ghost" onClick={() => handleSave(field.key, field.type)} disabled={isSaving}>
+                      <Button size="icon" variant="ghost" onClick={() => handleSave(field.key, field.type)} disabled={isSaving} aria-label="Save configuration" title="Save configuration">
                         <Check className="h-4 w-4 text-green-500" />
                       </Button>
-                      <Button size="icon" variant="ghost" onClick={handleCancel} disabled={isSaving}>
+                      <Button size="icon" variant="ghost" onClick={handleCancel} disabled={isSaving} aria-label="Cancel editing" title="Cancel editing">
                         <X className="h-4 w-4 text-red-500" />
                       </Button>
                     </div>
                   ) : (
-                    <Button size="icon" variant="ghost" onClick={() => handleEdit(field.key, currentValue)}>
+                    <Button size="icon" variant="ghost" onClick={() => handleEdit(field.key, currentValue)} aria-label="Edit configuration" title="Edit configuration">
                       <Pencil className="h-4 w-4" />
                     </Button>
                   )}