Participants, context menus, budget rename, file types, UI polish

- Assignment participants: toggle who joins each activity
  - Chips with hover-to-remove (strikethrough effect)
  - Add button with dropdown for available members
  - Avatars in day plan sidebar
  - Side-by-side with reservation in place inspector
- Right-click context menus for places, notes in day plan + places list
- Budget categories can now be renamed (pencil icon inline edit)
- Admin: configurable allowed file types (stored in app_settings)
- File manager shows allowed types dynamically
- Hotel picker: select place + save button (no auto-close)
- Edit pencil opens full hotel popup with all options
- Place inspector: opening hours + files side by side on desktop
- Address clamped to 2 lines, coordinates hidden on mobile
- Category shows icon only on mobile
- Rating hidden on mobile in place inspector
- Time validation: "10" becomes "10:00"
- Climate weather: full hourly data from archive API
- CustomSelect: grouped headers support (isHeader)
- Various responsive fixes

client/src/components/shared/CustomTimePicker.jsx

@@ -85,6 +85,9 @@ export default function CustomTimePicker({ value, onChange, placeholder = '00:00
       const h = Math.min(23, Math.max(0, parseInt(s.slice(0, 2))))
       const m = Math.min(59, Math.max(0, parseInt(s.slice(2))))
       onChange(String(h).padStart(2, '0') + ':' + String(m).padStart(2, '0'))
+    } else if (/^\d{1,2}$/.test(clean)) {
+      const h = Math.min(23, Math.max(0, parseInt(clean)))
+      onChange(String(h).padStart(2, '0') + ':00')
     }
   }