feat(vessel): Schiffsflotte im Profil und Logbuch-Auswahl

Benutzerweiter Vessel-Pool (E2E, Sync, Migration von Legacy-Yachts) mit
LogbookVesselSelection und LogbookVesselPicker. Profil mit Accordion
(Flotte & Crew); Demo und Onboarding-Tour inkl. profile_vessel_pool.

Co-authored-by: Cursor <cursoragent@cursor.com>

server/prisma/schema.prisma

@@ -24,6 +24,7 @@ model User {
   notificationPrefs        UserNotificationPrefs?
   appearancePrefs          UserAppearancePrefs?
   personPool                 PersonPayload[]
+  vesselPool                 VesselPayload[]
 }
 
 model PushSubscription {
@@ -88,6 +89,7 @@ model Logbook {
   yachts         YachtPayload[]
   crews          CrewPayload[]
   logbookCrewSelection LogbookCrewSelectionPayload?
+  logbookVesselSelection LogbookVesselSelectionPayload?
   deviations     DeviationPayload[]
   entries        EntryPayload[]
   photos         PhotoPayload[]
@@ -174,6 +176,30 @@ model LogbookCrewSelectionPayload {
   logbook       Logbook  @relation(fields: [logbookId], references: [id], onDelete: Cascade)
 }
 
+model VesselPayload {
+  id            String   @id @default(uuid())
+  userId        String
+  payloadId     String
+  encryptedData String
+  iv            String
+  tag           String
+  updatedAt     DateTime @updatedAt
+  user          User     @relation(fields: [userId], references: [id], onDelete: Cascade)
+
+  @@unique([userId, payloadId])
+  @@index([userId])
+}
+
+model LogbookVesselSelectionPayload {
+  id            String   @id @default(uuid())
+  logbookId     String   @unique
+  encryptedData String
+  iv            String
+  tag           String
+  updatedAt     DateTime @updatedAt
+  logbook       Logbook  @relation(fields: [logbookId], references: [id], onDelete: Cascade)
+}
+
 model DeviationPayload {
   id            String   @id @default(uuid())
   logbookId     String   @unique