fix(transport): resolve Invalid Date on bookings in relative Day N trips

Transport bookings on trips without calendar dates (relative "Day N" mode)
stored a malformed "T10:00" string in reservation_time. Every display
surface used includes('T') + new Date() which yielded Invalid Date.

Add splitReservationDateTime() helper that classifies any reservation_time
shape (full datetime, date-only, bare HH:MM, or legacy "T10:00") into
{ date, time } parts. Fix TransportModal to store a clean bare HH:MM
instead of "T10:00" and update the read-back path. Route all display
surfaces (ReservationsPanel, DayDetailPanel, DayPlanSidebar,
PlaceInspector, SharedTripPage, TripPDF) through the helper, gating the
DATE column on a real calendar date and the TIME column on a time part.
Guard the ICS export to skip time-only reservation_time values instead of
emitting a malformed DTSTART. Backward-compatible: existing saved rows
with "T10:00" render correctly without a data migration.

client/src/components/PDF/TripPDF.tsx

@@ -5,6 +5,7 @@ import { FileText, Info, Clock, MapPin, Navigation, Train, Plane, Bus, Car, Ship
 import { accommodationsApi, mapsApi } from '../../api/client'
 import type { Trip, Day, Place, Category, AssignmentsMap, DayNotesMap } from '../../types'
 import { isDayInAccommodationRange, getDayOrder } from '../../utils/dayOrder'
+import { splitReservationDateTime } from '../../utils/formatters'
 
 function renderLucideIcon(icon:LucideIcon, props = {}) {
   if (!_renderToStaticMarkup) return ''
@@ -216,7 +217,7 @@ export async function downloadTripPDF({ trip, days, places, assignments, categor
             const phase = pdfGetSpanPhase(r, day.id)
             const spanLabel = pdfGetSpanLabel(r, phase)
             const displayTime = pdfGetDisplayTime(r, day.id)
-            const time = displayTime?.includes('T') ? displayTime.split('T')[1]?.substring(0, 5) : ''
+            const time = splitReservationDateTime(displayTime).time ?? ''
             const titleHtml = `${spanLabel ? escHtml(spanLabel) + ': ' : ''}${escHtml(r.title)}`
             return `
               <div class="note-card" style="border-left: 3px solid ${color};">