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

src/components/AppDatePicker.vue

@@ -1,6 +1,7 @@
 <script setup lang="ts">
 import { ref, computed, watch, onBeforeUnmount, nextTick } from 'vue'
 import { Calendar, ChevronLeft, ChevronRight } from 'lucide-vue-next'
+import { getLocaleCode } from '../utils/locale'
 
 interface Props {
   modelValue: string
@@ -29,7 +30,7 @@ const displayText = computed(() => {
   if (!props.modelValue) return null
   const [y, m, d] = props.modelValue.split('-').map(Number)
   const date = new Date(y, m - 1, d)
-  return date.toLocaleDateString('en-US', {
+  return date.toLocaleDateString(getLocaleCode(), {
     month: 'short',
     day: 'numeric',
     year: 'numeric',
@@ -38,7 +39,7 @@ const displayText = computed(() => {
 
 const viewMonthLabel = computed(() => {
   const date = new Date(viewYear.value, viewMonth.value, 1)
-  return date.toLocaleDateString('en-US', { month: 'long', year: 'numeric' })
+  return date.toLocaleDateString(getLocaleCode(), { month: 'long', year: 'numeric' })
 })
 
 // ── Today helpers ───────────────────────────────────────────────────