GEN-3b: import notation normalization (Uw=G, Sls, deaf flag, tags)

genotype.py:
- Uw/uw aliased to G/g (same locus) so the D2 conflict group + pure-Uw
  cases stop being conflicts (Gg == Uwuw).
- Sls/WP recognized as a SECOND spotting locus (S(l)s(l)=WP het); carried
  into mapped8locus alongside Sp (Sp+Sls = Superschecke).
- dea/Dea/taub/hörend -> hearing/deaf phenotype FLAG (not a locus).
- WFNZ/RV/GV/DP -> provenance/breeding tags (not genotype, not conflicts).
- test_genotype.py: zero-dep unit tests for all four.

extract.py: surface deaf+tags on animals; dedup conflict detection now
compares the NORMALIZED genotype key (mapped8locus) instead of the raw
string, so Uw=G no longer triggers a conflict. Result: Konflikte 32 -> 27,
Zucht-Splits stays 0. Dedup identity = name + DOB + Zucht.

Backend: Gerbil.IsDeaf (bool?) + additive migration AddGerbilDeafFlag
(has-pending-model-changes clean) + GerbilDto/GerbilInput round-trip.
ImportService sets IsDeaf from animal.deaf and preserves Sls + tags + deaf
in RawImportData (kept out of the 8-locus compact Genotype contract until
GEN-3a adopts them).

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

GerbilManagerWebAPI/Dtos/ApiDtos.cs

@@ -27,7 +27,8 @@ namespace GerbilManagerWebAPI.Dtos
         string? ExternalRef,
         string? OriginBreeder,
         List<string> CharacterTraits,
-        string? CharacterNote);
+        string? CharacterNote,
+        bool? IsDeaf);
 
     public record LitterDto(
         Guid Id,
@@ -75,7 +76,8 @@ namespace GerbilManagerWebAPI.Dtos
         string? ExternalRef,
         string? OriginBreeder,
         List<string>? CharacterTraits,
-        string? CharacterNote);
+        string? CharacterNote,
+        bool? IsDeaf);
 
     public record LitterInput(
         string Name,