fix(ui): unify Lora Randomizer widget styles with Loras widget

Align visual design of Lora Randomizer widget with Loras widget for
consistent UI/UX across the node interface.

Changes:
- Unified border-radius system (4px→6px for containers, 6px for inputs)
- Standardized padding (12px→6px for widget container)
- Reduced slider height (32px→24px) following desktop tool best practices
- Aligned font sizes (12px→13px for labels, 11px→12px for buttons)
- Unified spacing system (16px→6px for sections, 8px→6px for gaps)
- Adjusted widget minimum height (510px→448px) to reflect layout changes

vue-widgets/src/components/LoraRandomizerWidget.vue

@@ -220,9 +220,9 @@ onMounted(async () => {
 
 <style scoped>
 .lora-randomizer-widget {
-  padding: 12px;
+  padding: 6px;
   background: rgba(40, 44, 52, 0.6);
-  border-radius: 4px;
+  border-radius: 6px;
   height: 100%;
   display: flex;
   flex-direction: column;