Rework entry types: merge hotel into stay, transport with modes, auto-transport

- Type set is now activity/stay/transport/flight/rental/note; hotel, travel
  and immigration are removed with idempotent startup data migrations
  (hotel->stay, travel->transport, immigration->activity with flag prefix)
- Transport entries carry an optional mode (train/bus/ferry/taxi/drive/other)
  that drives the chip/map icon; route stops expose transport_mode
- Creating a stay auto-creates a bridging transport to its neighbouring
  stays unless a transport/flight already covers the gap (one-shot)
- Summary: transports count replaces hotels/travelLegs

public/js/views/dayEditor.js

@@ -7,6 +7,7 @@ import { api } from '../api.js';
 import { el, clear, mount, toast } from '../dom.js';
 import {
   ENTRY_TYPE_LIST,
+  TRANSPORT_MODES,
   splitModeLabel,
   typeInfo,
   formatDate,
@@ -183,6 +184,7 @@ export function openDayEditor(tctx, date) {
     fields.start.value = entry.start_time || '';
     fields.end.value = entry.end_time || '';
     fields.endDate.value = entry.end_date || '';
+    fields.mode.value = entry.transport_mode || '';
     fields.cost.prefill(entry);
     // Flight segments (load() triggers the flight-route onChange -> UI sync).
     fields.flightRoute.load(Array.isArray(entry.segments) ? entry.segments : []);
@@ -223,6 +225,18 @@ export function openDayEditor(tctx, date) {
     locWrap.append(locInput, locResults, locSelected);
     const locationField = el('label', { class: 'field' }, el('span', { class: 'field-label' }, 'Location'), locWrap);
 
+    // ----- Transport mode (shown only for transport entries) -----
+    // Declared before the flight/rental subsections below: their onChange
+    // callbacks can call syncTypeUI() during construction (see the TDZ note
+    // below it), so anything syncTypeUI touches must already exist.
+    const modeSelect = el(
+      'select',
+      { class: 'input' },
+      el('option', { value: '' }, '—'),
+      ...TRANSPORT_MODES.map((m) => el('option', { value: m.value }, `${m.icon} ${m.label}`)),
+    );
+    const modeField = el('label', { class: 'field' }, el('span', { class: 'field-label' }, 'Mode'), modeSelect);
+
     // ----- Flight route subsection (shown only for flight entries) -----
     // The sub-modules fire onChange during construction (load of initial
     // state), before the section elements below exist — gate until wired.
@@ -253,6 +267,7 @@ export function openDayEditor(tctx, date) {
       const type = typeSelect.value;
       flightSection.style.display = type === 'flight' ? '' : 'none';
       rentalSection.style.display = type === 'rental' ? '' : 'none';
+      modeField.style.display = type === 'transport' ? '' : 'none';
       locationField.style.display = type === 'flight' && flightRoute.hasSegments() ? 'none' : '';
       // Stays emphasise an end date ("until"); other types call it "End date".
       endDateLabel.textContent = type === 'stay' ? 'Until' : 'End date';
@@ -267,7 +282,7 @@ export function openDayEditor(tctx, date) {
 
     fields = {
       type: typeSelect, title: titleInput, details: detailsInput, start: startInput, end: endInput,
-      endDate: endDateInput,
+      endDate: endDateInput, mode: modeSelect,
       locInput, locResults, locSelected,
       cost: costForm, flightRoute, rentalDetails,
     };
@@ -334,6 +349,10 @@ export function openDayEditor(tctx, date) {
         payload.rental = null;
       }
 
+      // Transport mode (transport entries only). Clear it otherwise so
+      // changing an entry's type away from transport drops any prior mode.
+      payload.transport_mode = typeSelect.value === 'transport' ? (modeSelect.value || null) : null;
+
       // end_date must be on/after the effective start date (rental may have
       // moved payload.date to the pickup date above).
       if (payload.end_date && payload.end_date < payload.date) {
@@ -383,6 +402,7 @@ export function openDayEditor(tctx, date) {
         'div',
         { class: 'form-row' },
         el('label', { class: 'field' }, el('span', { class: 'field-label' }, 'Type'), typeSelect),
+        modeField,
         el('label', { class: 'field field-grow' }, el('span', { class: 'field-label' }, 'Title'), titleInput),
       ),
       el('label', { class: 'field' }, el('span', { class: 'field-label' }, 'Details'), detailsInput),