<b>Pause and play</b>

Pause freezes the <i>display</i>, not the acquisition. The producer keeps filling the ring at
full rate; the view binds an immutable snapshot of the window that was on screen, and the axis
is pinned to it.

<b>How to reach it</b>

The pause button in the toolbar, or <tt>Space</tt>. Press it again to resume, which rebinds the
live ring and puts the window back on the newest data.

<b>Worth knowing</b>

• Nothing is lost while paused. Because the producer never stops, resuming shows current data
  with no hole in the history behind it.
• The axis is pinned to the <i>snapshot's own stamps</i>, not to the window that was requested.
  A window reaching back past the oldest retained sample yields a shorter snapshot, and the
  pinned axis is that shorter span — so you see a narrower view rather than an empty margin.
• A paused view is pinned exactly as a held trigger event is: zoom in freely, but a pan or a
  zoom out is clamped to the snapshot's data.
• Pausing is the easiest way to measure a layout or read a cursor precisely, because nothing
  under the pointer moves between frames.

<b>Example</b>

Pause with a 2 s window over a ring holding 1.4 s: the frozen axis reads
<tt>[-1.40 .. 0.00]</tt> rather than <tt>[-2.00 .. 0.00]</tt> with 0.6 s of blank. The pause
probe reports <tt>ring_produced</tt> still growing across the pause and
<tt>event_size</tt> non-zero exactly while paused.
