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/Import/ImportModels.cs

@@ -21,6 +21,11 @@ namespace GerbilManagerWebAPI.Import
         public List<string> SourceFiles { get; set; } = new();
         public bool Conflict { get; set; }
         public SourceLitterRef? LitterRef { get; set; }
+
+        // GEN-3b normalization: hearing/deaf phenotype flag (null = not stated) and
+        // provenance/breeding tags (WFNZ/RV/GV/DP) — neither is genotype.
+        public bool? Deaf { get; set; }
+        public List<string> Tags { get; set; } = new();
     }
 
     public sealed class SourceGenotype