DATA-2: new schema entities + Minimal API endpoints + Scalar + DAL teardown

- Entities: Breeder->Contact, +Enclosure/ColorVariety/GerbilPhoto/HealthRecord/WeightRecord;
  Gerbil expanded (single Genotype text col, Status/Gender enums-as-string, FK ids,
  ImportSource/ExternalRef provenance); Litter Strength->TotalBorn +ExpectedGoHomeDate/Notes.
  ColorVariety HasData seed = 18 from GEN-1 catalog. Gerbil<->Litter cycle handled
  (SetNull/Restrict). Enums stored as strings.
- Minimal API (no controllers): Endpoints/*.cs MapGroup+TypedResults for gerbils, litters,
  contacts, enclosures, color-varieties, health/weight-records, inbreeding (converted from
  controller, same routes/shapes), photos (Oscar contract: GET array/POST multipart/DELETE,
  url /photos/files/{fileName}). Gridify paged {items,totalCount,page,pageSize}, camelCase,
  409 conflict-deletes, flat FK ids, litter parent-gender validation (400 {code,...}).
- Scalar replaces Swashbuckle (AddOpenApi/MapOpenApi + MapScalarApiReference at /scalar);
  launchUrl swagger->scalar. GenericRepository/UnitOfWork/Converters deleted; DbContext direct.
- InbreedingService reads real FK props now; pure calculator + 8 tests untouched.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

GerbilManagerWebAPI/Models/Gerbil.cs

@@ -2,13 +2,49 @@ using System.ComponentModel.DataAnnotations;
 
 namespace GerbilManagerWebAPI.Models
 {
-    public record Gerbil
+    /// <summary>
+    /// A gerbil (Rennmaus). Pedigree is traversed via Litter → Father/Mother (no redundant
+    /// parent FKs here). Genotype is one compact frozen-contract string (e.g.
+    /// "Aa CC Dd EE GG Pp Spsp rere", "?" wildcards allowed); never SQL-filtered.
+    /// </summary>
+    public class Gerbil
     {
         [Key]
-        public Guid Id { get; init; } // init => properties are immutable by default, they are only mutable in the constructor and initializer.
-        public required string Name { get; set; } //required => parameter is necessary in constructor and object iniilization list. So it cannot be intantiated without it
-        public required Gender Gender { get; set; }
-        public Litter? Litter { get; set; } // Any variable where the ? isn't appended to the type name is a non-nullable reference type.
-        public Breeder? Breeder { get; set; } // You use the null-forgiving operator ! following a variable name to force the null-state to be not-null. For example, if you know the name variable isn't null but the compiler issues a warning, you can write the following code to override the compiler's analysis:
+        public Guid Id { get; set; }
+        public required string Name { get; set; }
+        public Gender Gender { get; set; }
+        public GerbilStatus Status { get; set; } = GerbilStatus.Active;
+
+        // Birth litter (the litter this gerbil was born in).
+        public Guid? LitterId { get; set; }
+        public Litter? Litter { get; set; }
+
+        // Contacts: Herkunft (origin) and Abnehmer (receiver, when given away).
+        public Guid? OriginContactId { get; set; }
+        public Contact? OriginContact { get; set; }
+        public Guid? ReceiverContactId { get; set; }
+        public Contact? ReceiverContact { get; set; }
+
+        // Current home.
+        public Guid? EnclosureId { get; set; }
+        public Enclosure? Enclosure { get; set; }
+
+        // Farbschlag.
+        public Guid? ColorVarietyId { get; set; }
+        public ColorVariety? ColorVariety { get; set; }
+
+        public DateOnly? DateOfBirth { get; set; }
+        public DateOnly? DateOfDeath { get; set; }
+        public string? CauseOfDeath { get; set; }
+        public DateOnly? GoHomeDate { get; set; }
+
+        /// <summary>Compact genotype string (frozen GEN-1 contract). Null = not genotyped.</summary>
+        public string? Genotype { get; set; }
+
+        public string? Notes { get; set; }
+
+        // Provenance (for the FEAT-8 spreadsheet import).
+        public string? ImportSource { get; set; }
+        public string? ExternalRef { get; set; }
     }
-}
+}