fix(capture): hold-to-record works by keyboard, confirms only after saving; drop FLAW-16

The + button lost its click handler for pointer events, so keyboard,
VoiceOver and switch control could no longer open the capture sheet; a
click without pointer (detail 0) now taps. "Im Quick Dump gespeichert"
appears after the save succeeded, and the cancel state uses an existing
border color. FLAW-16 (setup open until the first account, demo
accounts) is removed from the list: intended behaviour, not a flaw.

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

frontend/src/features/capture/__tests__/HoldToRecordFab.test.tsx

@@ -255,3 +255,12 @@ describe('HoldToRecordFab', () => {
     );
   });
 });
+
+describe('HoldToRecordFab keyboard access', () => {
+  it('opens the capture sheet when activated without a pointer (keyboard, screen reader)', () => {
+    const onTap = vi.fn();
+    const { getByRole } = render(<HoldToRecordFab onTap={onTap} onTranscript={vi.fn()} />);
+    fireEvent.click(getByRole('button'), { detail: 0 });
+    expect(onTap).toHaveBeenCalledTimes(1);
+  });
+});