Improve displaying how long ago pixels were placed

Fix date parsing for placement timestamps and add German language preference.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 0385ea33-cde8-4bbd-8fce-8d192d30eb41
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/870d08ce-da3b-4822-9874-c2fe2b7628b1/0385ea33-cde8-4bbd-8fce-8d192d30eb41/Vuy7IOw

client/src/components/color-palette.tsx

@@ -98,7 +98,7 @@ export function ColorPalette({
                   ({placement.x}, {placement.y})
                 </span>
                 <span className="text-xs text-muted" data-testid={`placement-time-${index}`}>
-                  {Math.floor((Date.now() - placement.createdAt.getTime()) / 1000)}s ago
+                  {Math.floor((Date.now() - new Date(placement.createdAt).getTime()) / 1000)}s ago
                 </span>
               </div>
             ))