feat(ui/templates): derived-template action and slimmer composition row

Right-click a template now offers "New Derived Template" — opens
TemplateCreate with the parent pre-selected via a new ?parentId query
parameter. Composition rows in the tree drop the trailing
"→ TargetName" muted text; the kind glyph plus the instance name carry
enough meaning, and the composed template is one click away from the
row's right-click menu.

tests/ScadaLink.CentralUI.Tests/TemplatesPageTests.cs

@@ -116,7 +116,9 @@ public class TemplatesPageTests : BunitContext
         ownerToggle!.Click();
 
         Assert.Contains("DelmiaReceiver", cut.Markup);
-        Assert.Contains("→", cut.Markup);
+        // The composition glyph appears via Bootstrap Icons; the composed template name
+        // is intentionally not rendered on the tree (V7 spec).
+        Assert.Contains("bi-arrow-return-right", cut.Markup);
     }
 
 }