fix(time-tracking) : return empty collection instead of 404 for active timer endpoint

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/services/time-entries.ts

@@ -24,8 +24,9 @@ export function useTimeEntryService() {
 
     async function getActive(): Promise<TimeEntry | null> {
         try {
-            const result = await api.get<TimeEntry | null>('/time_entries/active', {}, { toast: false })
-            return result ?? null
+            const data = await api.get<HydraCollection<TimeEntry>>('/time_entries/active', {}, { toast: false })
+            const members = extractHydraMembers(data)
+            return members[0] ?? null
         } catch {
             return null
         }