added status line info:

README.md

@@ -231,6 +231,30 @@ later, but the line marks the edge, so the pre/post split can be read straight o
 the plot. It is not one of the user's cursors: it has its own colour, ignores the
 cursor show/hide toggle, and is parked (invisible) when no event is held.
 
+**The status line.** It starts with an activity badge and then the mode, the
+connection, the measured rate, the packet/frame/gap counters, what plot 1 holds and
+the buffer's size and span. Three of those are worth calling out:
+
+- **The badge blinks green at 1 Hz while the pipeline is actually running** — the
+  stream is connected, acquisition is not paused, and in trigger mode the trigger is
+  armed. Anything else leaves it a steady grey, with the reason on its tooltip
+  (`paused`, `trigger disarmed`, `waiting for the stream`). *Blinking* is the signal,
+  not the colour: a steady badge is a stopped pipeline, and that distinction survives
+  a screenshot. It is one glyph whose colour is all that changes, so blinking it
+  cannot change its width — a badge that grew and shrank twice a second would move the
+  label beside it and re-lay out the plot with it.
+- **`rate 9.99 kS/s` is the rate the buffer actually stored over the last second**, not
+  the rate the CONFIG declared. The app does **no** decimation (see `plan_partition()`),
+  so the two normally agree and a gap between them is the datasource's real wire rate.
+  One figure when every channel agrees within a percent, `lo..hi` when they do not;
+  the per-channel breakdown, stored against declared, is on the line's tooltip. A
+  per-channel list in the line itself would make its width depend on the stream.
+- **`last event 12 s ago`** (trigger mode only) ages the picture on screen, in seconds,
+  then minutes, then hours. A frozen view looks the same whether the last event was a
+  second or an hour ago, so without it there is no way to tell a working trigger from
+  a dead one. Measured on the wall clock, not the stream's: it is a question about how
+  long *you* have been waiting. Before the first latch it reads `no event yet`.
+
 Switching the header bar's **trigger** button off returns to `[live]` and resumes
 drawing the stream; the trigger panel carries the same action as a
 **Go live (trigger off)** button, so the way out is inside the panel that froze