font re-work, change default to inter variable + fira code

Widgets/StyledText.qml

@@ -1,17 +1,34 @@
 import QtQuick
 import qs.Common
+import qs.Services
 
 Text {
     id: root
+    
+    property bool isMonospace: false
 
     color: Theme.surfaceText
     font.pixelSize: Appearance.fontSize.normal
-    font.family: Prefs.fontFamily
+    font.family: {
+        var requestedFont = isMonospace ? Prefs.monoFontFamily : Prefs.fontFamily
+        var defaultFont = isMonospace ? Prefs.defaultMonoFontFamily : Prefs.defaultFontFamily
+        
+        // If user hasn't overridden the font and we're using the default
+        if (requestedFont === defaultFont) {
+            var availableFonts = Qt.fontFamilies()
+            if (!availableFonts.includes(requestedFont)) {
+                // Use system default
+                return isMonospace ? "Monospace" : "DejaVu Sans"
+            }
+        }
+        
+        // Either user overrode it, or default font is available
+        return requestedFont
+    }
     font.weight: Prefs.fontWeight
     wrapMode: Text.WordWrap
     elide: Text.ElideRight
     verticalAlignment: Text.AlignVCenter
-    // Font rendering improvements for crisp text
     renderType: Text.NativeRendering
     textFormat: Text.PlainText
     antialiasing: true