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/Packing/PackingListPanel.jsx

@@ -8,36 +8,36 @@ import {
 } from 'lucide-react'
 
 const VORSCHLAEGE = [
-  { name: 'Reisepass', kategorie: 'Dokumente' },
-  { name: 'Reiseversicherung', kategorie: 'Dokumente' },
-  { name: 'Visum-Unterlagen', kategorie: 'Dokumente' },
-  { name: 'Flugtickets', kategorie: 'Dokumente' },
-  { name: 'Hotelbuchungen', kategorie: 'Dokumente' },
-  { name: 'Impfpass', kategorie: 'Dokumente' },
-  { name: 'T-Shirts (5×)', kategorie: 'Kleidung' },
-  { name: 'Hosen (2×)', kategorie: 'Kleidung' },
-  { name: 'Unterwäsche (7×)', kategorie: 'Kleidung' },
-  { name: 'Socken (7×)', kategorie: 'Kleidung' },
-  { name: 'Jacke', kategorie: 'Kleidung' },
-  { name: 'Badeanzug / Badehose', kategorie: 'Kleidung' },
-  { name: 'Sportschuhe', kategorie: 'Kleidung' },
-  { name: 'Zahnbürste', kategorie: 'Körperpflege' },
-  { name: 'Zahnpasta', kategorie: 'Körperpflege' },
-  { name: 'Shampoo', kategorie: 'Körperpflege' },
-  { name: 'Sonnencreme', kategorie: 'Körperpflege' },
-  { name: 'Deo', kategorie: 'Körperpflege' },
-  { name: 'Rasierer', kategorie: 'Körperpflege' },
-  { name: 'Ladekabel Handy', kategorie: 'Elektronik' },
-  { name: 'Reiseadapter', kategorie: 'Elektronik' },
-  { name: 'Kopfhörer', kategorie: 'Elektronik' },
-  { name: 'Kamera', kategorie: 'Elektronik' },
-  { name: 'Powerbank', kategorie: 'Elektronik' },
-  { name: 'Erste-Hilfe-Set', kategorie: 'Gesundheit' },
-  { name: 'Verschreibungspflichtige Medikamente', kategorie: 'Gesundheit' },
-  { name: 'Schmerzmittel', kategorie: 'Gesundheit' },
-  { name: 'Mückenschutz', kategorie: 'Gesundheit' },
-  { name: 'Bargeld', kategorie: 'Finanzen' },
-  { name: 'Kreditkarte', kategorie: 'Finanzen' },
+  { name: 'Passport', category: 'Documents' },
+  { name: 'Travel Insurance', category: 'Documents' },
+  { name: 'Visa Documents', category: 'Documents' },
+  { name: 'Flight Tickets', category: 'Documents' },
+  { name: 'Hotel Bookings', category: 'Documents' },
+  { name: 'Vaccination Card', category: 'Documents' },
+  { name: 'T-Shirts (5x)', category: 'Clothing' },
+  { name: 'Pants (2x)', category: 'Clothing' },
+  { name: 'Underwear (7x)', category: 'Clothing' },
+  { name: 'Socks (7x)', category: 'Clothing' },
+  { name: 'Jacket', category: 'Clothing' },
+  { name: 'Swimwear', category: 'Clothing' },
+  { name: 'Sport Shoes', category: 'Clothing' },
+  { name: 'Toothbrush', category: 'Toiletries' },
+  { name: 'Toothpaste', category: 'Toiletries' },
+  { name: 'Shampoo', category: 'Toiletries' },
+  { name: 'Sunscreen', category: 'Toiletries' },
+  { name: 'Deodorant', category: 'Toiletries' },
+  { name: 'Razor', category: 'Toiletries' },
+  { name: 'Phone Charger', category: 'Electronics' },
+  { name: 'Travel Adapter', category: 'Electronics' },
+  { name: 'Headphones', category: 'Electronics' },
+  { name: 'Camera', category: 'Electronics' },
+  { name: 'Power Bank', category: 'Electronics' },
+  { name: 'First Aid Kit', category: 'Health' },
+  { name: 'Prescription Medication', category: 'Health' },
+  { name: 'Pain Medication', category: 'Health' },
+  { name: 'Insect Repellent', category: 'Health' },
+  { name: 'Cash', category: 'Finances' },
+  { name: 'Credit Card', category: 'Finances' },
 ]
 
 // Cycling color palette — works in light & dark mode