feat: optimize routes around accommodation, confirm note deletions (#1123)

Optimize day routes around the accommodation

When a day has an accommodation set, the route optimizer now treats it as
the day's home base: it optimizes a loop that leaves the hotel and returns
to it, so the stop nearest the hotel comes first. On a transfer day -
checking out of one hotel and into another - the route runs from the first
hotel to the second instead.

The optimizer also gained a 2-opt pass on top of the nearest-neighbor
ordering, which removes the crossings the greedy pass used to leave behind.
A new display setting ("optimize route from accommodation", on by default)
lets you turn the anchoring off.

Confirm before deleting notes

Deleting a plan note or a collab note now asks for confirmation first. On
phones and tablets the edit and delete icons sit close together and were
easy to mis-tap, which deleted notes with no way back.

client/src/components/Collab/CollabNotesCard.tsx

@@ -16,7 +16,7 @@ interface NoteCardProps {
   currentUser: User
   canEdit: boolean
   onUpdate: (noteId: number, data: Partial<CollabNote>) => Promise<void>
-  onDelete: (noteId: number) => Promise<void>
+  onDelete: (noteId: number) => void
   onEdit: (note: CollabNote) => void
   onView: (note: CollabNote) => void
   onPreviewFile: (file: NoteFile) => void