Derive client domain types from the shared schema contracts

Add entity/response Zod schemas to @trek/shared (place, trip, assignment, day, budget, packing, reservation), each matched against the producing server service, and re-export them from client types.ts instead of the hand-written duplicates that had drifted (name/title, amount/total_price, owner_id/user_id, cover_url/cover_image, ...). Updates the call sites and test fixtures the corrected types surfaced; type-only, no runtime behaviour change.

client/src/components/Planner/PlaceInspector.tsx

@@ -104,6 +104,7 @@ function formatFileSize(bytes) {
 interface TripMember {
   id: number
   username: string
+  avatar?: string | null
   avatar_url?: string | null
 }