Task #19: Force Latin digits + redesign home screen

- New helper artifacts/teaboy-os/src/lib/i18n-format.ts wraps Intl with
  numberingSystem: "latn" so numerals always render 0-9 even in Arabic,
  while month/weekday names stay localized. Exports formatTime,
  formatDate, formatHijri, formatWeekday, formatDateTime, formatNumber
  and a greetingKey() helper for time-of-day greetings.

- Replaced every toLocaleTimeString / toLocaleDateString /
  toLocaleString / direct Intl.DateTimeFormat call in home, admin,
  chat and notifications with the new helpers. No remaining
  Arabic-Indic digits anywhere in the UI (verified e2e).

- Redesigned the home screen:
    * Tighter status bar with three balanced sections: identity (avatar
      + name + admin tag), centered clock + Hijri/Gregorian dates,
      grouped controls (language, bell, logout).
    * Personal greeting line ("Good morning / صباح الخير …") driven by
      local hour and the user's display name.
    * Admin-only 4-card stat row (Apps / Services / Messages / Alerts)
      with soft glass + small colored icon tiles.
    * Polished apps grid with section count badge and a friendly empty
      state. Drag-and-drop reorder behavior preserved.
    * Type-safe Lucide icon resolver (no unsafe casts).

- Added i18n keys home.greeting.{morning,afternoon,evening},
  home.noApps, home.noAppsHint, home.stats.* in ar.json and en.json.

- Cleaned up obsolete follow-up plan file now that this work shipped.

Verified via TypeScript + e2e Playwright run in both Arabic (RTL) and
English (LTR): login → home redesign → notifications → chat, all
numerals Latin in both languages.

artifacts/teaboy-os/src/components/ui/calendar.tsx

@@ -37,7 +37,7 @@ function Calendar({
       captionLayout={captionLayout}
       formatters={{
         formatMonthDropdown: (date) =>
-          date.toLocaleString("default", { month: "short" }),
+          new Intl.DateTimeFormat("en-US-u-nu-latn", { month: "short", numberingSystem: "latn" }).format(date),
         ...formatters,
       }}
       classNames={{
@@ -190,7 +190,7 @@ function CalendarDayButton({
       ref={ref}
       variant="ghost"
       size="icon"
-      data-day={day.date.toLocaleDateString()}
+      data-day={new Intl.DateTimeFormat("en-US-u-nu-latn", { numberingSystem: "latn" }).format(day.date)}
       data-selected-single={
         modifiers.selected &&
         !modifiers.range_start &&

artifacts/teaboy-os/src/components/ui/chart.tsx

@@ -240,7 +240,7 @@ const ChartTooltipContent = React.forwardRef<
                         </div>
                         {item.value && (
                           <span className="font-mono font-medium tabular-nums text-foreground">
-                            {item.value.toLocaleString()}
+                            {new Intl.NumberFormat("en-US-u-nu-latn", { numberingSystem: "latn" }).format(Number(item.value))}
                           </span>
                         )}
                       </div>