feat: replace all hardcoded en-US and $ formatting with locale-aware helpers

src/views/Entries.vue

@@ -231,6 +231,7 @@ import AppSelect from '../components/AppSelect.vue'
 import AppDatePicker from '../components/AppDatePicker.vue'
 import { useEntriesStore, type TimeEntry } from '../stores/entries'
 import { useProjectsStore } from '../stores/projects'
+import { formatDate } from '../utils/locale'
 
 const entriesStore = useEntriesStore()
 const projectsStore = useProjectsStore()
@@ -316,16 +317,6 @@ function formatDuration(seconds: number): string {
   return `${minutes}m`
 }
 
-// Format date
-function formatDate(dateString: string): string {
-  const date = new Date(dateString)
-  return date.toLocaleDateString('en-US', {
-    month: 'short',
-    day: 'numeric',
-    year: 'numeric'
-  })
-}
-
 // Apply filters
 function applyFilters() {
   entriesStore.fetchEntries(startDate.value || undefined, endDate.value || undefined)