feat(transport): add bus, taxi, bicycle, ferry and other transport types (#1105)

Closes #718. Adds five new transport reservation types alongside the
existing flight/train/car/cruise: bus, taxi, bicycle, ferry and a generic
'transport_other' catch-all. The new types are treated as first-class
transports everywhere — the transport modal, day plan, route calculation,
map overlays, file grouping and the PDF export — and are translated across
all 20 locales.

A dedicated 'transport_other' value is used for the catch-all so existing
'other' bookings are not reclassified as transport.

client/src/utils/dayMerge.ts

@@ -1,4 +1,4 @@
-export const TRANSPORT_TYPES = new Set(['flight', 'train', 'bus', 'car', 'cruise'])
+export const TRANSPORT_TYPES = new Set(['flight', 'train', 'bus', 'car', 'taxi', 'bicycle', 'cruise', 'ferry', 'transport_other'])
 
 export interface MergedItem {
   type: 'place' | 'note' | 'transport'