OWNERSHIP: residency classification (Bestand vs external ancestors)

Per hive/agents/god/OWNERSHIP-residency.md (Julian): "Clan kleine Chaoten"
is the wife's own Zucht. Classify each animal:
 (a) RESIDENT if zuchtCanon contains 'kleinechaote' (separator/declension-
     insensitive: "v.d. Kleinen Chaoten", "Clan-Kleine-Chaoten", …); OR
 (b) PARENT EXCEPTION — a parent of a Clan offspring is resident even if its
     own Zuchtname is foreign (you can only breed a Clan litter if the parents
     were in your care). Runs AFTER the parentRefs→litter linking.
Otherwise EXTERNAL (pedigree ancestor, not living stock — kept, not deleted).

Stored as a dedicated Gerbil.IsResident bool (distinct from Status/Abgabe —
origin/identity, not current location), defaulting true (own stock unless
marked external; DB HasDefaultValue(true)). Additive migration
AddGerbilResidency; has-pending-model-changes clean. Round-trips in
GerbilDto/GerbilInput and is Gridify-filterable (isResident==true) so Kevin
can build a "nur Bestand" filter. ImportService computes it at (re-)import
and refreshes existing rows on the idempotent sweep. ResidencySummary added
to the import report.

Projected on real data: 306 loadable → 227 resident (188 rule a, +39 via
parent exception), 79 external ancestors.

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

GerbilManagerWebAPI/Import/ImportModels.cs

@@ -16,6 +16,7 @@ namespace GerbilManagerWebAPI.Import
         public List<string> FarbschlagVariants { get; set; } = new();
         public SourceGenotype Genotype { get; set; } = new();
         public string Zucht { get; set; } = "";
+        public string ZuchtCanon { get; set; } = "";       // declension-folded Zucht key (residency rule a)
         public List<SourceParentRef> ParentRefs { get; set; } = new();
         public List<string> Photos { get; set; } = new();
         public List<string> SourceFiles { get; set; } = new();
@@ -73,7 +74,12 @@ namespace GerbilManagerWebAPI.Import
         AnimalSummary Animals,
         PhotoSummary Photos,
         IReadOnlyList<string> Samples,
-        IReadOnlyList<string> Notes);
+        IReadOnlyList<string> Notes,
+        ResidencySummary? Residency = null);
+
+    /// <summary>Bestand (resident) vs external pedigree ancestors; FlippedByParentRule = foreign-
+    /// Zuchtname animals made resident because they parented a Clan offspring (rule b).</summary>
+    public sealed record ResidencySummary(int Resident, int External, int FlippedByParentRule);
 
     public sealed record LitterSummary(int InSource, int Created, int AlreadyImported, int DerivedFromChart = 0);