Adds website theme serialization system

src/app/admin/admin.component.html

@@ -22,7 +22,7 @@
       <button class="tab-btn" [class.active]="activeTab() === 'underwriters'"
         (click)="activeTab.set('underwriters')">Underwriters</button>
       <button class="tab-btn" [class.active]="activeTab() === 'mobile-builds'"
-        (click)="activeTab.set('mobile-builds')">Mobile Builds</button>
+        (click)="activeTab.set('mobile-builds'); loadThemeJsonStatus()">Mobile Builds</button>
       <button class="tab-btn" [class.active]="activeTab() === 'stats'" (click)="activeTab.set('stats')">Stats</button>
     </div>
 
@@ -437,6 +437,33 @@
           }
         </section>
 
+        <section class="build-card">
+          <h3>Theme Export</h3>
+          @if (themeJsonStatus$ | async; as status) {
+          @if (status.exists) {
+          <div class="theme-status-ok">
+            <div><strong>theme.json</strong> — ready</div>
+            <div>Path: {{ status.path }}</div>
+            <div>Generated: {{ status.generated_at }}</div>
+            <div>Size: {{ status.size }} bytes</div>
+          </div>
+          } @else {
+          <div class="theme-status-missing">
+            <p><strong>theme.json</strong> not found at {{ status.path }}</p>
+            <p>Regenerate to create it from the current station config.</p>
+          </div>
+          }
+          <button class="btn btn-outline" (click)="regenerateThemeJson()"
+            [disabled]="themeJsonLoading$ | async">
+            {{ (themeJsonLoading$ | async) ? 'Regenerating...' : 'Regenerate' }}
+          </button>
+          } @else {
+          @if (themeJsonLoading$ | async) {
+          <p class="empty-row">Loading...</p>
+          }
+          }
+        </section>
+
         <section class="build-card">
           <h3>Create Build Request</h3>