Repaint the phone's chrome, radii and accent to the v5 vocabulary

src/DodoSSH.Client.Android/Views/PhoneRail.axaml

@@ -36,6 +36,18 @@
     The .railentry styles live in this file because they are this control's own shape and nothing else wears
     them; every colour in them is resolved from Theme/Palette.axaml by key, which is the rule that matters —
     a rail that named its own blues is how a fifth surface colour ends up in the application.
+
+    ── DEEP CHROME, SINCE v5 ───────────────────────────────────────────────────────────────────────────────
+    This rail's own surface moves from Sidebar to DeepChrome in this pass, matching the desktop's NavRail —
+    which is exactly what this control is standing in for on a wide phone, and which took the same v5b move
+    itself: Palette.axaml's own remark on DeepChrome names "the rail down the side" as one of the five things
+    that colour is for. Sidebar stays what a card sits on; this is the frame the cards sit inside, the same
+    distinction PhoneShell's header, strip and bottom bar are drawing at the same time.
+
+    The hover fill moves too, from Panel to Track — and Track rather than Hover, because Palette.axaml's own
+    remark on Track names "the rail row a pointer sits over" as one of the three things that colour is for,
+    literally. Panel was never named for this; it read close enough that nobody had gone looking for the
+    seam, which is exactly the kind of gap Track exists to close.
   -->
 
   <UserControl.Styles>
@@ -54,7 +66,7 @@
     </Style>
 
     <Style Selector="Button.railentry:pointerover /template/ ContentPresenter">
-      <Setter Property="Background" Value="{StaticResource Panel}" />
+      <Setter Property="Background" Value="{StaticResource Track}" />
     </Style>
 
     <Style Selector="Button.railentry.active /template/ ContentPresenter">
@@ -96,7 +108,7 @@
     </Style>
   </UserControl.Styles>
 
-  <Border Width="188" Background="{StaticResource Sidebar}"
+  <Border Width="188" Background="{StaticResource DeepChrome}"
           BorderBrush="{StaticResource Border}" BorderThickness="0,0,1,0">
 
     <!--