A counter that increments once per live notification arrival, for replaying
the bell's ring animation. Re-key the bell glyph on it — remounting the
element restarts the CSS bell-ring keyframes, which a class toggle alone
would not:
Pulses on a hidden tab are ignored — an animation nobody saw is not
worth replaying when they come back. Starts at 0 so the bell doesn't ring on
first mount (the initial SSE snapshot is not an "arrival").
A counter that increments once per live notification arrival, for replaying the bell's ring animation. Re-key the bell glyph on it — remounting the element restarts the CSS
bell-ringkeyframes, which a class toggle alone would not: