feat(stats): add note ID resolution and session event handling improvements

- Add note ID resolution through merge redirects in stats API
- Build Anki note previews using configured field names
- Add session event helpers for merged note dedup and stable request keys
- Refactor SessionDetail to prevent redundant note info requests
- Add session event popover and API client tests

stats/src/components/overview/QuickStats.tsx

@@ -38,7 +38,7 @@ export function QuickStats({ rollups }: QuickStatsProps) {
         </div>
         <div className="flex justify-between">
           <span className="text-ctp-subtext0">Cards this week</span>
-          <span className="text-ctp-green font-medium">{weekCards}</span>
+          <span className="text-ctp-cards-mined font-medium">{weekCards}</span>
         </div>
       </div>
     </div>