correcting pixiv connection functionality

frontend/src/views/Credentials.vue

@@ -104,7 +104,11 @@
 
         <v-card-text>
           <v-alert type="info" variant="tonal" class="mb-4">
-            <template v-if="uploadPlatform?.auth_type === 'token'">
+            <template v-if="uploadPlatformKey === 'pixiv'">
+              Paste your Pixiv OAuth refresh token below.
+              Run <code>gallery-dl oauth:pixiv</code> to obtain one.
+            </template>
+            <template v-else-if="uploadPlatform?.auth_type === 'token'">
               Paste your Discord user token below.
               <strong>Never share your token with anyone!</strong>
             </template>
@@ -128,7 +132,17 @@
                 How to get {{ uploadPlatform?.auth_type === 'token' ? 'your token' : 'cookies' }}
               </v-expansion-panel-title>
               <v-expansion-panel-text>
-                <template v-if="uploadPlatform?.auth_type === 'token'">
+                <template v-if="uploadPlatformKey === 'pixiv'">
+                  <ol>
+                    <li>Install gallery-dl: <code>pip install gallery-dl</code></li>
+                    <li>Run: <code>gallery-dl oauth:pixiv</code></li>
+                    <li>A browser window will open for Pixiv login</li>
+                    <li>After authorizing, copy the refresh token displayed</li>
+                    <li>Paste the token here</li>
+                  </ol>
+                  <p class="mt-2 text-caption">The refresh token is a long string that gallery-dl uses to authenticate with Pixiv's API.</p>
+                </template>
+                <template v-else-if="uploadPlatform?.auth_type === 'token'">
                   <ol>
                     <li>Open Discord in your browser</li>
                     <li>Press F12 to open Developer Tools</li>
@@ -285,6 +299,9 @@ function openUploadDialog(platform, info) {
 }
 
 function getPlaceholder() {
+  if (uploadPlatformKey.value === 'pixiv') {
+    return 'AZX1abc2DEF3ghi...'
+  }
   if (uploadPlatform.value?.auth_type === 'token') {
     return 'mfa.AbCdEf123456...'
   }