Main: Overview UI icon buttons authoring

Scene edits wiring the new Icon Button prefab/icons into the Overview
menu (includes the usual re-save YAML reshuffle) plus TMP font SDF
atlas churn from the UI work.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Assets/Fonts/arialroundedmtprocyr_bold SDF.asset

@@ -55791,7 +55791,7 @@ Material:
     - _Reflectivity: 10
     - _ScaleRatioA: 0.8888889
     - _ScaleRatioB: 0.7222222
-    - _ScaleRatioC: 0.65656567
+    - _ScaleRatioC: 0.5777778
     - _ScaleX: 1
     - _ScaleY: 1
     - _ShaderFlags: 0
@@ -55804,10 +55804,10 @@ Material:
     - _StencilWriteMask: 255
     - _TextureHeight: 1024
     - _TextureWidth: 1024
-    - _UnderlayDilate: 0.7
+    - _UnderlayDilate: 1
     - _UnderlayOffsetX: 0
     - _UnderlayOffsetY: 0
-    - _UnderlaySoftness: 0.4
+    - _UnderlaySoftness: 0.25
     - _VertexOffsetX: 0
     - _VertexOffsetY: 0
     - _WeightBold: 0.75