feat: add vendor dropdown and show_in_legal to content page editor

- Load vendors dynamically in content page editor dropdown
- Add show_in_legal field to default content pages seed script
- Set privacy and terms pages to show_in_legal=true, show_in_footer=false
- Update page creation in seed script to use show_in_legal

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/templates/admin/content-page-edit.html

@@ -90,12 +90,16 @@
                     <select
                         x-model="form.vendor_id"
                         class="w-full px-3 py-2 text-gray-700 dark:text-gray-300 border border-gray-300 dark:border-gray-600 rounded-lg focus:outline-none focus:border-purple-500 dark:bg-gray-700"
+                        :disabled="loadingVendors"
                     >
                         <option :value="null">Platform Default</option>
-                        <!-- TODO: Load vendors dynamically if needed -->
+                        <template x-for="vendor in vendors" :key="vendor.id">
+                            <option :value="vendor.id" x-text="vendor.name"></option>
+                        </template>
                     </select>
                     <p class="mt-1 text-xs text-gray-500 dark:text-gray-400">
-                        Platform defaults are shown to all vendors
+                        <span x-show="!form.vendor_id">Platform defaults are shown to all vendors</span>
+                        <span x-show="form.vendor_id">This page will only be visible for the selected vendor</span>
                     </p>
                 </div>
             </div>