feat(kol): support multiple platform hints with shared tag renderer

Turn the KOL prompt platform hint into a multi-select backed by the
media platforms API, persist hints as a 、-joined string, and add a
reusable KolPlatformTags component so manage/generate/package/template/
workspace views and the generate-task drawer all render the hints
consistently with truncation and overflow handling.

Also auto-select the first available subscription prompt in
GenerateTaskDrawer when switching to the subscription-prompt target so
users land on a usable option without an extra click.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/admin-web/src/views/KolGenerateView.vue

@@ -1,6 +1,7 @@
 <script setup lang="ts">
 import KnowledgeGroupSelect from '@/components/KnowledgeGroupSelect.vue'
 import KolDynamicForm from '@/components/kol/KolDynamicForm.vue'
+import KolPlatformTags from '@/components/kol/KolPlatformTags.vue'
 import { kolGenerateApi } from '@/lib/api'
 import { formatError } from '@/lib/errors'
 import { parseKolCardConfig } from '@/lib/kol-card-config'
@@ -150,10 +151,14 @@ function handleSubmit() {
               {{ schema.package_name }}
               <span class="divider">/</span>
               {{ schema.prompt_name }}
-              <a-tag v-if="schema.platform_hint" color="cyan" class="platform-badge">
-                {{ schema.platform_hint }}
-              </a-tag>
             </h2>
+            <KolPlatformTags
+              v-if="schema.platform_hint"
+              :value="schema.platform_hint"
+              size="small"
+              :truncate="false"
+              class="platform-badge"
+            />
             <p class="header-eyebrow">{{ t('kol.generate.fillVariables') }}</p>
           </div>
         </div>
@@ -268,7 +273,7 @@ function handleSubmit() {
 }
 
 .platform-badge {
-  margin-left: 8px;
+  margin-top: 2px;
 }
 
 .header-eyebrow {