feat(mobile): today marked on the day rail, and a button back to it

While a trip is running, today's chip on the phone carries a ring and a dot, and a button beside the rail jumps back to today from wherever it was scrolled, in the plan and on the map. It stays in place, dimmed, while today is open, so the rail never shifts under the thumb. (#2392)

client/src/mobile/screens/trip/MTripShell.tsx

@@ -1,8 +1,7 @@
 import { useEffect, useRef, useState, type ComponentType, type ReactNode } from 'react'
-import { findFocusDayId } from '../../../components/Planner/today'
+import { findFocusDayId, findTodayDayId } from '../../../components/Planner/today'
 import {
-  CalendarDays, ChevronDown, ChevronLeft, Download, FileDown, List, Map as MapIcon, MoreHorizontal,
-  FolderSync, Plane, Plus, Rows3, Route, SlidersHorizontal, Trash2, Upload,
+  CalendarCheck, CalendarDays, ChevronDown, ChevronLeft, Download, FileDown, FolderSync, List, Map as MapIcon, MoreHorizontal, Plane, Plus, Route, Rows3, SlidersHorizontal, Trash2, Upload,
 } from 'lucide-react'
 import { useTripPlanner } from '../../../pages/tripPlanner/useTripPlanner'
 import { pickDockTabs } from './dockTabs'
@@ -405,6 +404,15 @@ export default function MTripShell({
   const dockTabs = pickDockTabs(enabledTabIds)
   const tabLabel = (id: string) => planner.TRIP_TABS.find(tab => tab.id === id)?.label ?? id
 
+  // While the trip runs, today's chip carries a ring and a button jumps back to it
+  // from wherever the rail was scrolled (#2392). Null outside the trip's dates.
+  const todayDayId = findTodayDayId(days)
+  const jumpToToday = () => {
+    if (todayDayId == null || todayDayId === planner.selectedDayId) return
+    if (view === 'map') selectDayOnMap(todayDayId)
+    else planner.handleSelectDay(todayDayId, true)
+  }
+
   const onDayChipTap = (dayId: number) => {
     if (dayId === planner.selectedDayId) openSheet('day', { dayId })
     // In map mode a day tap fits to that day's places, draws its route and drops
@@ -483,6 +491,7 @@ export default function MTripShell({
           <div className="flex flex-1 items-center gap-[2px] overflow-x-auto rounded-full border border-[color:var(--m-gbr)] bg-[color:var(--m-glass)] p-[3px] backdrop-blur-[24px] backdrop-saturate-[1.7]">
             {days.map((day, idx) => {
               const active = day.id === planner.selectedDayId
+              const isToday = day.id === todayDayId
               const tint = dayTints[day.id]
               return (
                 <button
@@ -496,11 +505,16 @@ export default function MTripShell({
                   // Inactive chips only — an inline background would otherwise beat
                   // the active chip's bg-m-act class.
                   style={active ? undefined : { background: dayTintBackground(tint, 'badge', '--day-tint-chip') }}
+                  data-today={isToday || undefined}
                   className={`flex flex-1 items-center justify-center gap-[3px] whitespace-nowrap rounded-full px-3 py-[5px] text-center text-[0.75rem] font-semibold ${
                     active ? 'bg-m-act text-m-actfg shadow-[0_6px_16px_-6px_rgba(0,0,0,.4)]' : 'text-m-ink'
-                  }`}
+                  } ${isToday && !active ? 'ring-[1.5px] ring-inset ring-[color:var(--m-st-info)]' : ''}`}
                 >
+                  {isToday && (
+                    <span aria-hidden="true" className={`h-[5px] w-[5px] flex-none rounded-full ${active ? 'bg-m-actfg' : 'bg-[color:var(--m-st-info)]'}`} />
+                  )}
                   {dayChipLabel(day, language, t('planner.dayN', { n: day.day_number ?? idx + 1 }))}
+                  {isToday && <span className="sr-only">{t('mobileTrip.today')}</span>}
                   {/* Marks the second tap as "opens the day", the only day-sheet
                       route that also exists in map view. */}
                   {active && <ChevronDown size={11} strokeWidth={2.6} aria-hidden="true" className="flex-none opacity-70" />}
@@ -508,6 +522,20 @@ export default function MTripShell({
               )
             })}
           </div>
+          {/* Back to today from anywhere on the rail (#2392). Mounted for the whole
+              running trip and dimmed while today is already open, so it never
+              appears under the thumb and shoves the rail aside. */}
+          {todayDayId != null && (
+            <button
+              type="button"
+              onClick={jumpToToday}
+              disabled={todayDayId === planner.selectedDayId}
+              aria-label={t('mobileTrip.jumpToToday')}
+              className="flex w-9 flex-none items-center justify-center rounded-full border border-[color:var(--m-gbr)] bg-[color:var(--m-glass)] text-[color:var(--m-st-info)] backdrop-blur-[24px] backdrop-saturate-[1.7] transition-opacity disabled:opacity-40"
+            >
+              <CalendarCheck size={15} strokeWidth={2.4} aria-hidden="true" />
+            </button>
+          )}
           {/* Drop the day filter and show the whole trip (#2257). Map only: the
               plan timeline and the road trip chain are both single-day, so there is
               nothing to widen there. Stays mounted while a day is active rather than