feat: navigation

backend/uframe/layout.py

@@ -8,7 +8,7 @@ from uframe.ir import (
     Gauge, Sparkline, Status, Table,
     Form, Field, Password, Radio, Checkbox, FormButton,
     Let, Source, IfBlock, ForLoop, CacheControl, OnSubmit, StateDecl,
-    BigTitle, ImageNode,
+    BigTitle, ImageNode, HNav, VNav,
 )
 
 
@@ -137,7 +137,7 @@ def layout(node: IRNode, x: int, y: int, w: int, h: int) -> int:
     elif isinstance(node, (Heading, Text, Label, Divider, Link, ListItem,
                            Gauge, Sparkline, Status, Table,
                            Field, Password, Radio, Checkbox, FormButton,
-                           BigTitle, ImageNode)):
+                           BigTitle, ImageNode, HNav, VNav)):
         node.rect.h = node.pref_height
         return node.pref_height