feat(client): make dashboard greeting respect user timezone

Calculate the dashboard greeting using the user's configured timezone from
account settings. Additionally, add a "night" greeting category for hours
between 00:00 and 04:59, and update the clock/time state every minute to
ensure the greeting stays accurate over time.

Closes #551

client/src/features/dashboard/lib/greeting.test.ts

@@ -0,0 +1,38 @@
+import { describe, expect, it } from 'vitest'
+
+import { getDashboardGreetingLabel, getHourInTimeZone, resolveDashboardGreetingTimeZone } from './greeting'
+
+describe('dashboard greeting', () => {
+  it.each([
+    ['00:00', 'night', '2025-12-31T16:00:00.000Z'],
+    ['04:59', 'night', '2025-12-31T20:59:00.000Z'],
+    ['05:00', 'morning', '2025-12-31T21:00:00.000Z'],
+    ['11:59', 'morning', '2026-01-01T03:59:00.000Z'],
+    ['12:00', 'afternoon', '2026-01-01T04:00:00.000Z'],
+    ['17:59', 'afternoon', '2026-01-01T09:59:00.000Z'],
+    ['18:00', 'evening', '2026-01-01T10:00:00.000Z'],
+    ['23:59', 'evening', '2026-01-01T15:59:00.000Z'],
+  ])('returns Asia/Shanghai %s as %s', (_localTime, expected, instant) => {
+    expect(getDashboardGreetingLabel(new Date(instant), 'Asia/Shanghai')).toBe(expected)
+  })
+
+  it('uses the configured timezone instead of the browser timezone', () => {
+    const instant = new Date('2026-01-01T21:30:00.000Z')
+
+    expect(getDashboardGreetingLabel(instant, 'UTC')).toBe('evening')
+    expect(getDashboardGreetingLabel(instant, 'Asia/Shanghai')).toBe('morning')
+  })
+
+  it('falls back to UTC when the configured timezone is missing or invalid', () => {
+    const instant = new Date('2026-01-01T03:30:00.000Z')
+
+    expect(resolveDashboardGreetingTimeZone(undefined)).toBe('UTC')
+    expect(resolveDashboardGreetingTimeZone('Invalid/Zone')).toBe('UTC')
+    expect(getDashboardGreetingLabel(instant, 'Asia/Shanghai')).toBe('morning')
+    expect(getDashboardGreetingLabel(instant, 'Invalid/Zone')).toBe('night')
+  })
+
+  it('extracts midnight as hour zero', () => {
+    expect(getHourInTimeZone(new Date('2025-12-31T16:00:00.000Z'), 'Asia/Shanghai')).toBe(0)
+  })
+})

client/src/features/dashboard/lib/greeting.ts

@@ -0,0 +1,45 @@
+export type DashboardGreetingLabel = 'night' | 'morning' | 'afternoon' | 'evening'
+
+const DEFAULT_TIME_ZONE = 'UTC'
+
+export function resolveDashboardGreetingTimeZone(value: string | null | undefined): string {
+  const normalized = value?.trim()
+  if (!normalized) return DEFAULT_TIME_ZONE
+
+  try {
+    new Intl.DateTimeFormat('en-US', { timeZone: normalized })
+    return normalized
+  } catch {
+    return DEFAULT_TIME_ZONE
+  }
+}
+
+export function getHourInTimeZone(date: Date, timeZone: string): number {
+  if (Number.isNaN(date.getTime())) {
+    throw new RangeError('Invalid date')
+  }
+
+  const formatter = new Intl.DateTimeFormat('en-US', {
+    timeZone: resolveDashboardGreetingTimeZone(timeZone),
+    hour: '2-digit',
+    hourCycle: 'h23',
+  })
+  const hourPart = formatter.formatToParts(date).find((part) => part.type === 'hour')?.value
+  const hour = Number(hourPart)
+
+  if (hour === 24) return 0
+  if (!Number.isInteger(hour) || hour < 0 || hour > 23) {
+    throw new RangeError('Invalid timezone hour')
+  }
+
+  return hour
+}
+
+export function getDashboardGreetingLabel(date: Date, timeZone: string | null | undefined): DashboardGreetingLabel {
+  const hour = getHourInTimeZone(date, resolveDashboardGreetingTimeZone(timeZone))
+
+  if (hour < 5) return 'night'
+  if (hour < 12) return 'morning'
+  if (hour < 18) return 'afternoon'
+  return 'evening'
+}

client/src/views/DashboardView.vue

@@ -1,9 +1,10 @@
 <script setup lang="ts">
-import { computed, nextTick, onMounted, ref, watch } from 'vue'
+import { computed, nextTick, onMounted, onUnmounted, ref, watch } from 'vue'
 import { Settings2, Sparkles } from '@lucide/vue'
 import { Tooltip, TooltipContent, TooltipTrigger } from '@/components/ui/tooltip'
 
 import { useAuth } from '@/features/auth/composables/useAuth'
+import { getDashboardGreetingLabel } from '@/features/dashboard/lib/greeting'
 import { usePermissions } from '@/features/auth/composables/usePermissions'
 import { useLibraries } from '@/features/library/composables/useLibraries'
 import DashboardScroller from '@/features/dashboard/components/DashboardScroller.vue'
@@ -22,6 +23,8 @@ const { maybeStartTour } = useOnboardingTour()
 const { smartScopes, loaded: smartScopesLoaded, fetchSmartScopes } = useSmartScopes()
 
 const settingsOpen = ref(false)
+const now = ref(new Date())
+let greetingTimer: number | null = null
 
 const enabledScrollers = computed(() =>
   (Array.isArray(scrollers.value) ? scrollers.value : []).filter((s) => s.enabled).sort((a, b) => a.order - b.order),
@@ -29,10 +32,7 @@ const enabledScrollers = computed(() =>
 
 const hasNoLibraries = computed(() => !librariesLoading.value && libraries.value.length === 0)
 const greetingLabel = computed(() => {
-  const hour = new Date().getHours()
-  if (hour < 12) return 'morning'
-  if (hour < 18) return 'afternoon'
-  return 'evening'
+  return getDashboardGreetingLabel(now.value, user.value?.settings?.timezone)
 })
 const greetingName = computed(() => {
   const fullName = user.value?.name?.trim()
@@ -52,10 +52,20 @@ watch(
 onMounted(() => {
   fetchLibraries()
   fetchSmartScopes()
+  greetingTimer = window.setInterval(() => {
+    now.value = new Date()
+  }, 60_000)
   nextTick(() => {
     setTimeout(maybeStartTour, 500)
   })
 })
+
+onUnmounted(() => {
+  if (greetingTimer !== null) {
+    window.clearInterval(greetingTimer)
+    greetingTimer = null
+  }
+})
 </script>
 
 <template>