fix: standardize relative timestamping (#3612)

* fix(frontend): relative timestamps are incorrectly rounded.

Closes: #1371

* fix(all): remove legacy fromNow for proper relative timestamp creation

Closes: #1395

packages/ui/src/composables/how-ago.ts

@@ -0,0 +1,23 @@
+import { createFormatter, type FormatOptions, type Formatter } from '@vintl/how-ago'
+import type { IntlController } from '@vintl/vintl/controller'
+import { useVIntl } from '@vintl/vintl'
+import { computed } from 'vue'
+
+/* eslint-disable @typescript-eslint/no-explicit-any */
+const formatters = new WeakMap<IntlController<any>, Formatter>()
+
+export function useRelativeTime(): Formatter {
+  const vintl = useVIntl()
+
+  let formatter = formatters.get(vintl)
+
+  if (formatter == null) {
+    const formatterRef = computed(() => createFormatter(vintl.intl))
+    const defaultOptions: FormatOptions = { roundingMode: 'halfExpand' as const }
+
+    formatter = (value, options) => formatterRef.value(value, { ...options, ...defaultOptions })
+    formatters.set(vintl, formatter)
+  }
+
+  return formatter
+}

packages/ui/src/composables/index.ts

@@ -0,0 +1 @@
+export * from './how-ago'