v2.5.7: Reservation overhaul, Day Detail Panel, i18n, paste support, auto dark mode

BREAKING: Reservations have been completely rebuilt. Existing place-level
reservations are no longer used. All reservations must be re-created via
the Bookings tab. Your trips, places, and other data are unaffected.

Reservation System (rebuilt from scratch):
- Reservations now link to specific day assignments instead of places
- Same place on different days can have independent reservations
- New assignment picker in booking modal (grouped by day, searchable)
- Removed day/place dropdowns from booking form
- Reservation badges in day plan sidebar with type-specific icons
- Reservation details in place inspector (only for selected assignment)
- Reservation summary in day detail panel

Day Detail Panel (new):
- Opens on day click in the sidebar
- Detailed weather: hourly forecast, precipitation, wind, sunrise/sunset
- Historical climate averages for dates beyond 16 days
- Accommodation management with check-in/check-out, confirmation number
- Hotel assignment across multiple days with day range picker
- Reservation overview for the day

Places:
- Places can now be assigned to the same day multiple times
- Start time + end time fields (replaces single time field)
- Map badges show multiple position numbers (e.g. "1 · 4")
- Route optimization fixed for duplicate places
- File attachments during place editing (not just creation)
- Cover image upload during trip creation (not just editing)
- Paste support (Ctrl+V) for images in trip, place, and file forms

Internationalization:
- 200+ hardcoded German strings translated to i18n (EN + DE)
- Server error messages in English
- Category seeds in English for new installations
- All planner, register, photo, packing components translated

UI/UX:
- Auto dark mode (follows system preference, configurable in settings)
- Navbar toggle switches light/dark (overrides auto)
- Sidebar minimize buttons z-index fixed
- Transport mode selector removed from day plan
- CustomSelect supports grouped headers (isHeader option)
- Optimistic updates for day notes (instant feedback)
- Booking cards redesigned with type-colored headers and structured details

Weather:
- Wind speed in mph when using Fahrenheit setting
- Weather description language matches app language

Admin:
- Weather info panel replaces OpenWeatherMap key input
- "Recommended" badge styling updated

client/src/components/Photos/PhotoGallery.jsx

@@ -3,8 +3,10 @@ import { PhotoLightbox } from './PhotoLightbox'
 import { PhotoUpload } from './PhotoUpload'
 import { Upload, Camera } from 'lucide-react'
 import Modal from '../shared/Modal'
+import { useTranslation } from '../../i18n'
 
 export default function PhotoGallery({ photos, onUpload, onDelete, onUpdate, places, days, tripId }) {
+  const { t } = useTranslation()
   const [lightboxIndex, setLightboxIndex] = useState(null)
   const [showUpload, setShowUpload] = useState(false)
   const [filterDayId, setFilterDayId] = useState('')
@@ -49,7 +51,7 @@ export default function PhotoGallery({ photos, onUpload, onDelete, onUpdate, pla
           onChange={e => setFilterDayId(e.target.value)}
           className="border border-gray-200 rounded-lg px-3 py-1.5 text-sm text-gray-600 focus:outline-none focus:ring-2 focus:ring-slate-900"
         >
-          <option value="">Alle Tage</option>
+          <option value="">{t('photos.allDays')}</option>
           {(days || []).map(day => (
             <option key={day.id} value={day.id}>
               Tag {day.day_number}{day.date ? ` · ${formatDate(day.date)}` : ''}
@@ -62,7 +64,7 @@ export default function PhotoGallery({ photos, onUpload, onDelete, onUpdate, pla
             onClick={() => setFilterDayId('')}
             className="text-xs text-gray-500 hover:text-gray-700 underline"
           >
-            Zurücksetzen
+            {t('common.reset')}
           </button>
         )}
 
@@ -80,8 +82,8 @@ export default function PhotoGallery({ photos, onUpload, onDelete, onUpdate, pla
         {filteredPhotos.length === 0 ? (
           <div style={{ textAlign: 'center', padding: '60px 20px', color: '#9ca3af' }}>
             <Camera size={40} style={{ color: '#d1d5db', display: 'block', margin: '0 auto 12px' }} />
-            <p style={{ fontSize: 14, fontWeight: 600, color: '#374151', margin: '0 0 4px' }}>Noch keine Fotos</p>
-            <p style={{ fontSize: 13, color: '#9ca3af', margin: '0 0 20px' }}>Lade deine Reisefotos hoch</p>
+            <p style={{ fontSize: 14, fontWeight: 600, color: '#374151', margin: '0 0 4px' }}>{t('photos.noPhotos')}</p>
+            <p style={{ fontSize: 13, color: '#9ca3af', margin: '0 0 20px' }}>{t('photos.uploadHint')}</p>
             <button
               onClick={() => setShowUpload(true)}
               className="flex items-center gap-2 bg-slate-900 text-white px-6 py-3 rounded-xl hover:bg-slate-700 font-medium"
@@ -109,7 +111,7 @@ export default function PhotoGallery({ photos, onUpload, onDelete, onUpdate, pla
               className="aspect-square rounded-xl border-2 border-dashed border-gray-200 hover:border-slate-400 flex flex-col items-center justify-center gap-2 text-gray-400 hover:text-slate-700 transition-colors"
             >
               <Upload className="w-6 h-6" />
-              <span className="text-xs">Hinzufügen</span>
+              <span className="text-xs">{t('common.add')}</span>
             </button>
           </div>
         )}

client/src/components/Photos/PhotoLightbox.jsx

@@ -1,7 +1,9 @@
 import React, { useState, useEffect, useCallback } from 'react'
 import { X, ChevronLeft, ChevronRight, Edit2, Trash2, Check } from 'lucide-react'
+import { useTranslation } from '../../i18n'
 
 export function PhotoLightbox({ photos, initialIndex, onClose, onUpdate, onDelete, days, places, tripId }) {
+  const { t } = useTranslation()
   const [index, setIndex] = useState(initialIndex || 0)
   const [editCaption, setEditCaption] = useState(false)
   const [caption, setCaption] = useState('')
@@ -81,7 +83,7 @@ export function PhotoLightbox({ photos, initialIndex, onClose, onUpdate, onDelet
             <button
               onClick={handleDelete}
               className="p-2 text-white/60 hover:text-red-400 hover:bg-white/10 rounded-lg transition-colors"
-              title="Löschen"
+              title={t('common.delete')}
             >
               <Trash2 className="w-4 h-4" />
             </button>

client/src/components/Photos/PhotoUpload.jsx

@@ -1,8 +1,10 @@
 import React, { useState, useCallback } from 'react'
 import { useDropzone } from 'react-dropzone'
 import { Upload, X, Image } from 'lucide-react'
+import { useTranslation } from '../../i18n'
 
 export function PhotoUpload({ tripId, days, places, onUpload, onClose }) {
+  const { t } = useTranslation()
   const [files, setFiles] = useState([])
   const [dayId, setDayId] = useState('')
   const [placeId, setPlaceId] = useState('')
@@ -78,7 +80,7 @@ export function PhotoUpload({ tripId, days, places, onUpload, onClose }) {
         ) : (
           <>
             <p className="text-gray-600 font-medium">Fotos hier ablegen</p>
-            <p className="text-gray-400 text-sm mt-1">oder klicken zum Auswählen</p>
+            <p className="text-gray-400 text-sm mt-1">{t('photos.clickToSelect')}</p>
             <p className="text-gray-400 text-xs mt-2">JPG, PNG, WebP · max. 10 MB · bis zu 30 Fotos</p>
           </>
         )}
@@ -128,13 +130,13 @@ export function PhotoUpload({ tripId, days, places, onUpload, onClose }) {
             </select>
           </div>
           <div>
-            <label className="block text-xs font-medium text-gray-700 mb-1">Ort verknüpfen</label>
+            <label className="block text-xs font-medium text-gray-700 mb-1">{t('photos.linkPlace')}</label>
             <select
               value={placeId}
               onChange={e => setPlaceId(e.target.value)}
               className="w-full border border-gray-200 rounded-lg px-3 py-2 text-sm focus:outline-none focus:ring-2 focus:ring-slate-900"
             >
-              <option value="">Kein Ort</option>
+              <option value="">{t('photos.noPlace')}</option>
               {(places || []).map(place => (
                 <option key={place.id} value={place.id}>{place.name}</option>
               ))}
@@ -175,7 +177,7 @@ export function PhotoUpload({ tripId, days, places, onUpload, onClose }) {
           onClick={onClose}
           className="px-4 py-2 text-sm text-gray-600 border border-gray-200 rounded-lg hover:bg-gray-50"
         >
-          Abbrechen
+          {t('common.cancel')}
         </button>
         <button
           onClick={handleUpload}
@@ -183,7 +185,7 @@ export function PhotoUpload({ tripId, days, places, onUpload, onClose }) {
           className="flex items-center gap-2 px-6 py-2 bg-slate-900 text-white text-sm rounded-lg hover:bg-slate-700 disabled:opacity-60 font-medium"
         >
           <Upload className="w-4 h-4" />
-          {uploading ? 'Hochladen...' : `${files.length} Foto${files.length !== 1 ? 's' : ''} hochladen`}
+          {uploading ? t('common.uploading') : t('photos.uploadN', { n: files.length })}
         </button>
       </div>
     </div>