fix: dynamic currency symbols and integrated datetime picker

- Replace all hardcoded prefix="$" with :prefix="getCurrencySymbol()"
  in Settings, Projects, and Invoices views
- Replace hardcoded ($) labels with dynamic currency symbol
- Extend AppDatePicker with showTime prop + hour/minute v-models
  for integrated date+time selection
- Simplify Entries.vue to use single AppDatePicker with showTime
  instead of separate hour/minute inputs

src/components/AppDatePicker.vue

@@ -6,14 +6,22 @@ import { getLocaleCode } from '../utils/locale'
 interface Props {
   modelValue: string
   placeholder?: string
+  showTime?: boolean
+  hour?: number
+  minute?: number
 }
 
 const props = withDefaults(defineProps<Props>(), {
   placeholder: 'Select date',
+  showTime: false,
+  hour: 0,
+  minute: 0,
 })
 
 const emit = defineEmits<{
   'update:modelValue': [value: string]
+  'update:hour': [value: number]
+  'update:minute': [value: number]
 }>()
 
 const isOpen = ref(false)
@@ -30,13 +38,44 @@ 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(getLocaleCode(), {
+  const datePart = date.toLocaleDateString(getLocaleCode(), {
     month: 'short',
     day: 'numeric',
     year: 'numeric',
   })
+  if (props.showTime) {
+    const hh = String(props.hour).padStart(2, '0')
+    const mm = String(props.minute).padStart(2, '0')
+    return `${datePart} ${hh}:${mm}`
+  }
+  return datePart
 })
 
+// ── Time helpers ──────────────────────────────────────────────────────
+const internalHour = ref(props.hour)
+const internalMinute = ref(props.minute)
+
+watch(() => props.hour, (v) => { internalHour.value = v })
+watch(() => props.minute, (v) => { internalMinute.value = v })
+
+function onHourInput(e: Event) {
+  const val = parseInt((e.target as HTMLInputElement).value)
+  if (!isNaN(val)) {
+    const clamped = Math.min(23, Math.max(0, val))
+    internalHour.value = clamped
+    emit('update:hour', clamped)
+  }
+}
+
+function onMinuteInput(e: Event) {
+  const val = parseInt((e.target as HTMLInputElement).value)
+  if (!isNaN(val)) {
+    const clamped = Math.min(59, Math.max(0, val))
+    internalMinute.value = clamped
+    emit('update:minute', clamped)
+  }
+}
+
 const viewMonthLabel = computed(() => {
   const date = new Date(viewYear.value, viewMonth.value, 1)
   return date.toLocaleDateString(getLocaleCode(), { month: 'long', year: 'numeric' })
@@ -354,6 +393,28 @@ onBeforeUnmount(() => {
           </button>
         </div>
 
+        <!-- Time inputs (when showTime is true) -->
+        <div v-if="showTime" class="border-t border-border-subtle px-3 py-2.5 flex items-center justify-center gap-2">
+          <span class="text-[0.6875rem] text-text-tertiary uppercase tracking-[0.08em]">Time</span>
+          <input
+            :value="String(internalHour).padStart(2, '0')"
+            type="number"
+            min="0"
+            max="23"
+            @input="onHourInput"
+            class="w-11 px-1.5 py-1 bg-bg-inset border border-border-subtle rounded-lg text-[0.8125rem] text-text-primary text-center font-mono focus:outline-none focus:border-border-visible [appearance:textfield] [&::-webkit-outer-spin-button]:appearance-none [&::-webkit-inner-spin-button]:appearance-none"
+          />
+          <span class="text-text-tertiary text-sm font-mono">:</span>
+          <input
+            :value="String(internalMinute).padStart(2, '0')"
+            type="number"
+            min="0"
+            max="59"
+            @input="onMinuteInput"
+            class="w-11 px-1.5 py-1 bg-bg-inset border border-border-subtle rounded-lg text-[0.8125rem] text-text-primary text-center font-mono focus:outline-none focus:border-border-visible [appearance:textfield] [&::-webkit-outer-spin-button]:appearance-none [&::-webkit-inner-spin-button]:appearance-none"
+          />
+        </div>
+
         <!-- Today shortcut -->
         <div class="border-t border-border-subtle px-3 py-2">
           <button