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/Properties/launchSettings.json

@@ -13,7 +13,7 @@
       "commandName": "Project",
       "dotnetRunMessages": true,
       "launchBrowser": true,
-      "launchUrl": "swagger",
+      "launchUrl": "scalar",
       "applicationUrl": "http://localhost:5179",
       "environmentVariables": {
         "ASPNETCORE_ENVIRONMENT": "Development"
@@ -23,7 +23,7 @@
       "commandName": "Project",
       "dotnetRunMessages": true,
       "launchBrowser": true,
-      "launchUrl": "swagger",
+      "launchUrl": "scalar",
       "applicationUrl": "https://localhost:7191;http://localhost:5179",
       "environmentVariables": {
         "ASPNETCORE_ENVIRONMENT": "Development"
@@ -32,7 +32,7 @@
     "IIS Express": {
       "commandName": "IISExpress",
       "launchBrowser": true,
-      "launchUrl": "swagger",
+      "launchUrl": "scalar",
       "environmentVariables": {
         "ASPNETCORE_ENVIRONMENT": "Development"
       }