fix(06-04): add global pulse keyframe and drop redundant spin redefinition

- Add @keyframes pulse (0%,100% opacity:1; 50% opacity:0.4) to tokens.css after @keyframes spin
- Remove redundant local <style> block redefining @keyframes spin from PushPermissionPrompt.tsx
- LiveSyncIndicator reconnecting dot now resolves its pulse animation from the global stylesheet
- PushPermissionPrompt spinner continues to work via the existing global spin keyframe

apps/pwa/src/components/PushPermissionPrompt.tsx

@@ -354,13 +354,6 @@ export function PushPermissionPrompt({ onClose }: PushPermissionPromptProps) {
         </div>
       </div>
 
-      {/* Spin animation for loader */}
-      <style>{`
-        @keyframes spin {
-          from { transform: rotate(0deg); }
-          to { transform: rotate(360deg); }
-        }
-      `}</style>
     </div>
   )
 }