feat: implement emergency duty (Notdienst) swapping for parents

prisma/schema.prisma

@@ -84,6 +84,13 @@ enum NotdienstAlertStatus {
   CANCELLED
 }
 
+enum NotdienstSwapStatus {
+  PENDING
+  ACCEPTED
+  DECLINED
+  CANCELLED
+}
+
 enum DutyAssignmentStatus {
   PLANNED
   DONE
@@ -136,6 +143,7 @@ model Kita {
   notdienstAvailabilities NotdienstAvailability[]
   notdienstAssignments    NotdienstAssignment[]
   notdienstAlerts         NotdienstAlert[]
+  notdienstSwapRequests   NotdienstSwapRequest[]
 
   @@map("kitas")
 }
@@ -158,6 +166,7 @@ model Family {
   users           User[]
   children        Child[]
   dutyAssignments DutyAssignment[]
+  notdienstSwapRequestsStarted NotdienstSwapRequest[] @relation("NotdienstSwapRequesterFamily")
 
   @@index([kitaId])
   @@map("families")
@@ -219,6 +228,8 @@ model User {
   notdienstAlertsAssigned  NotdienstAlert[]        @relation("NotdienstAlertParent")
   notdienstAlertsTriggered NotdienstAlert[]        @relation("NotdienstAlertTrigger")
   notdienstPlansCreated    NotdienstPlan[]         @relation("NotdienstPlanCreator")
+  notdienstSwapRequestsStarted   NotdienstSwapRequest[] @relation("NotdienstSwapRequester")
+  notdienstSwapRequestsResponded NotdienstSwapRequest[] @relation("NotdienstSwapResponder")
   announcementsAuthored    Announcement[]          @relation("AnnouncementAuthor")
   announcementReads        AnnouncementRead[]
 
@@ -647,12 +658,50 @@ model NotdienstAssignment {
   updatedAt DateTime @updatedAt
 
   alerts NotdienstAlert[]
+  swapRequestsAsTarget  NotdienstSwapRequest[] @relation("NotdienstSwapTargetAssignment")
+  swapRequestsAsOffered NotdienstSwapRequest[] @relation("NotdienstSwapOfferedAssignment")
 
   @@unique([planId, date])
   @@index([kitaId, date])
   @@map("notdienst_assignments")
 }
 
+/// Tauschanfrage zwischen Eltern fuer zwei bereits veroeffentlichte
+/// zukuenftige Notdienst-Zuteilungen.
+model NotdienstSwapRequest {
+  id     String @id @default(cuid())
+  kitaId String
+  kita   Kita   @relation(fields: [kitaId], references: [id], onDelete: Cascade)
+
+  requesterUserId String
+  requesterUser   User   @relation("NotdienstSwapRequester", fields: [requesterUserId], references: [id], onDelete: Cascade)
+
+  requesterFamilyId String
+  requesterFamily   Family @relation("NotdienstSwapRequesterFamily", fields: [requesterFamilyId], references: [id], onDelete: Cascade)
+
+  targetAssignmentId String
+  targetAssignment   NotdienstAssignment @relation("NotdienstSwapTargetAssignment", fields: [targetAssignmentId], references: [id], onDelete: Cascade)
+
+  offeredAssignmentId String
+  offeredAssignment   NotdienstAssignment @relation("NotdienstSwapOfferedAssignment", fields: [offeredAssignmentId], references: [id], onDelete: Cascade)
+
+  status NotdienstSwapStatus @default(PENDING)
+  message String?
+
+  respondedById String?
+  respondedBy   User?   @relation("NotdienstSwapResponder", fields: [respondedById], references: [id], onDelete: SetNull)
+  respondedAt   DateTime?
+
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+
+  @@index([kitaId, status])
+  @@index([requesterFamilyId, status])
+  @@index([targetAssignmentId, status])
+  @@index([offeredAssignmentId, status])
+  @@map("notdienst_swap_requests")
+}
+
 /// Aktive Alarmierung — wird bei Krankmeldung einer Fachkraft
 /// vom Koordinator ausgelöst. Bestätigung via Magic-Link (Token).
 model NotdienstAlert {