ui: a signal's details sit directly under its name; its unit is user-changeable and saved with the session

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

help/C/org.udpscope.app/signals.page

@@ -30,9 +30,10 @@
       </item>
       <item>
         <p>Once a signal is acquired its badge appears. Click it to open that signal's page: its
-        colour, <gui>Plot on</gui> buttons for the rows, <gui>Information</gui> for the signal's
-        details, and its <gui>Gain</gui> and <gui>Offset</gui>, each with a pencil button that
-        edits that one number.</p>
+        details directly under its name — <gui>Unit</gui>, <gui>Gain</gui> and <gui>Offset</gui>,
+        each with a pencil button that edits that one value, then the type, size, range, sample
+        rate and timing the stream declared — its colour and <gui>Plot on</gui> buttons for the
+        rows.</p>
       </item>
     </steps>
   </section>
@@ -47,7 +48,9 @@
       through, so a trace already scaled by a gain of 2 reads 2. The pencil beside a number opens
       an editor for that number only, at its current value —
       pressing <gui>Apply</gui> confirms it rather than resetting it. A signal nobody
-      calibrated shows the identity, 1 and 0.</p></item>
+      calibrated shows the identity, 1 and 0. The unit can be renamed the same way (an empty
+      entry restores the one the stream declares); the new name is used in the readouts, the
+      measurements and the export, and is remembered with the session.</p></item>
       <item><p>Calibration is applied <em>at ingest</em>, so changing it re-plans the buffer
       and drops the history. So does enabling or disabling a signal, and so does a new
       CONFIG. An empty plot for a second after one of those is the ring refilling, not a