fix(web): disable the enlarge button along with its field

Copilot review round 2 on #2109. A disabled form (a tool call in flight) left
the enlarge button live, and activating it swapped in a text area that mounts
disabled — so the focus hand-off targeted an unfocusable element and keyboard
focus was dropped to the document.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JTHVxSu8AUgHRLvo1ntZ8H
Signed-off-by: cliffhall <cliff@futurescale.com>

clients/web/src/components/elements/EnlargeButton/EnlargeButton.test.tsx

@@ -33,4 +33,14 @@ describe("EnlargeButton", () => {
       screen.getByRole("button", { name: "Enlarge Query" }),
     ).toBeInTheDocument();
   });
+
+  it("is inert when the field it belongs to is disabled", async () => {
+    const user = userEvent.setup();
+    const onClick = vi.fn();
+    renderWithMantine(<EnlargeButton onClick={onClick} disabled />);
+    const button = screen.getByRole("button", { name: "Enlarge" });
+    expect(button).toBeDisabled();
+    await user.click(button);
+    expect(onClick).not.toHaveBeenCalled();
+  });
 });

clients/web/src/components/elements/EnlargeButton/EnlargeButton.tsx

@@ -11,6 +11,12 @@ export interface EnlargeButtonProps {
    * tell them apart; the visible tooltip stays the plain verb.
    */
   ariaLabel?: string;
+  /**
+   * Mirrors the disabled state of the input this sits in. A live button on a
+   * disabled field would still swap in the text area — which mounts disabled and
+   * cannot take focus, dropping keyboard focus to the document.
+   */
+  disabled?: boolean;
 }
 
 const EnlargeActionIcon = ActionIcon.withProps({
@@ -34,10 +40,18 @@ const EnlargeActionIcon = ActionIcon.withProps({
  * of the tab order without cost; entering multiline mode has none, so removing
  * this one would put the feature out of reach of keyboard users entirely.
  */
-export function EnlargeButton({ onClick, ariaLabel }: EnlargeButtonProps) {
+export function EnlargeButton({
+  onClick,
+  ariaLabel,
+  disabled,
+}: EnlargeButtonProps) {
   return (
     <Tooltip label="Enlarge">
-      <EnlargeActionIcon aria-label={ariaLabel ?? "Enlarge"} onClick={onClick}>
+      <EnlargeActionIcon
+        aria-label={ariaLabel ?? "Enlarge"}
+        disabled={disabled}
+        onClick={onClick}
+      >
         <ImEnlarge2 size={12} />
       </EnlargeActionIcon>
     </Tooltip>