fix(upload-model): UI/UX improvements for Upload Model Dialog (#7969)

## Summary

Addresses UI/UX feedback on the Upload Model Dialog (BYOM feature).

## Changes

1. **Standardize link styling** - Use consistent `text-muted-foreground
underline` for all links in both URL input variants
2. **Increase warning/example text font size** - Changed from 12px
(`text-xs`) to 14px (`text-sm`) for better readability
3. **Fix padding inconsistency** - Aligned padding between model name
box and SingleSelect dropdown; moved "Not sure?" help text inline with
the label
4. **Add "Upload Another" button** - Allows users to upload multiple
models without closing and reopening the dialog

## Testing

- Verified link styling consistency across both Civitai and generic URL
input components
- Confirmed padding alignment in confirmation step
- Tested Upload Another button resets wizard to step 1

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7969-fix-upload-model-UI-UX-improvements-for-Upload-Model-Dialog-2e66d73d3650815c8184cedb3d02672d)
by [Unito](https://www.unito.io)

src/platform/assets/composables/useUploadModelWizard.ts

@@ -284,6 +284,20 @@ export function useUploadModelWizard(modelTypes: Ref<ModelTypeOption[]>) {
     }
   }
 
+  function resetWizard() {
+    currentStep.value = 1
+    isFetchingMetadata.value = false
+    isUploading.value = false
+    uploadStatus.value = undefined
+    uploadError.value = ''
+    wizardData.value = {
+      url: '',
+      name: '',
+      tags: []
+    }
+    selectedModelType.value = undefined
+  }
+
   return {
     // State
     currentStep,
@@ -302,6 +316,7 @@ export function useUploadModelWizard(modelTypes: Ref<ModelTypeOption[]>) {
     // Actions
     fetchMetadata,
     uploadModel,
-    goToPreviousStep
+    goToPreviousStep,
+    resetWizard
   }
 }