feat(abgabe): Reservierungs-/Abgabe-Status (verfügbar/reserviert/abgegeben)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

GerbilManagerWebAPI/ApplicationContext.cs

@@ -25,6 +25,7 @@ public class ApplicationContext : DbContext
     public DbSet<Request> Requests => Set<Request>();
     public DbSet<MailSettings> MailSettings => Set<MailSettings>();
     public DbSet<Feedback> Feedback => Set<Feedback>();
+    public DbSet<SaleReservation> SaleReservations => Set<SaleReservation>();
 
     // Keep Gerbil.NameSearch in sync on every save (separator-insensitive search key),
     // so it can never drift from Name regardless of which code path mutates the entity.
@@ -212,6 +213,16 @@ public class ApplicationContext : DbContext
             e.HasIndex(f => f.CreatedAt);
         });
 
+        // ABGABE-STATUS: deliberately relationship-free (same rationale as Feedback).
+        // GerbilId/ReservedForContactId are plain Guid columns (no navigation properties →
+        // EF creates NO foreign key), so the import re-ingest wipe of Gerbils/Contacts never
+        // cascades into — or breaks — reservation rows. They survive re-ingest by design.
+        modelBuilder.Entity<SaleReservation>(e =>
+        {
+            e.Property(r => r.Price).HasPrecision(10, 2);
+            e.HasIndex(r => r.GerbilId);
+        });
+
         // DB-4: German collation on remaining searched/sorted text columns (Npgsql-only).
         if (isNpgsql)
         {