docs: the manual and the user guide describe the badge bar, the dock and the slide-over pages

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

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

@@ -22,10 +22,12 @@
     <title>How to reach it</title>
     <steps>
       <item>
-        <p>Press the math button in the toolbar, or <key>g</key>.</p>
+        <p>Open the <gui>Signals</gui> page (the <gui>+</gui> badge, or <key>g</key>). Math channels
+        are listed under a <gui>MATH</gui> heading.</p>
       </item>
       <item>
-        <p>The pane's <gui>+</gui> adds a channel, and opening one shows the graph editor:
+        <p>The heading's <gui>+</gui> adds a channel. <gui>Edit graph</gui>, on a channel's page,
+        shows the graph editor:
         nodes as boxes, click a box to select it and edit its parameters beside the canvas.</p>
       </item>
       <item>
@@ -53,7 +55,7 @@
       <em>above</em> it. A wire drawn right to left re-sorts the list silently so the graph
       stays valid. A cycle is unrepresentable: the connection is refused rather than created,
       and the line beneath the form says why — a loop, or a node asked to read itself.</p></item>
-      <item><p>A derived channel <em>is</em> a channel. It appears in the signal panel, can be
+      <item><p>A derived channel <em>is</em> a channel. It is listed with the signals, gets a badge once computed, can be
       plotted, measured, exported, and used as a source for another math channel.</p></item>
       <item><p>The math runs on the <em>stored</em> samples — decimated and averaged — so a
       cutoff you type in Hz means the rate the filter will actually run at. Change the window