CommandRow: * icon, SRC: label, remove separator, clean margins

- Replace diamond with * for pixel-perfect fold alignment
- Add SRC: label prefix to command row source field
- Remove vertical bar separator from command row
- Clear footer margin text (no more ---)
- Remove + prefix from offset margin (0x instead of +0x)
- Remove codicon font infrastructure (use editor font chars)

src/resources.qrc

@@ -5,5 +5,6 @@
   </qresource>
   <qresource prefix="/fonts">
     <file alias="Iosevka-Regular.ttf">fonts/Iosevka-Regular.ttf</file>
+    <file alias="codicon.ttf">fonts/codicon.ttf</file>
   </qresource>
 </RCC>