topdata: stop hardcoding the skills dataset location

The skills dataset moved into a tree (skills/core, skills/specs, ...).
Resolve it data-driven instead of by name:

- The required-family check no longer pins skill focus families to
  dataset "skills"; the family spec's child_source names the dataset.
- Affinity generation and display names use the skill_focus spec's
  child_source dataset.
- Child slugs derive from the row key's own namespace (text after the
  first colon) instead of assuming namespace == dataset path.
- The wiki loader accepts both layouts ("skills", then "skills/core").

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

internal/topdata/topdata.go

@@ -1867,8 +1867,10 @@ func validateGeneratedFeatFamilies(dataDir string, report *ValidationReport) {
 	}
 
 	required := []requiredFeatFamily{
-		{FamilyKey: "skillfocus", Dataset: "skills", Predicate: "accessible"},
-		{FamilyKey: "greaterskillfocus", Dataset: "skills", Predicate: "accessible"},
+		// skill families: the source dataset is data-driven (family spec), only
+		// the accessibility predicate is required
+		{FamilyKey: "skillfocus", Predicate: "accessible"},
+		{FamilyKey: "greaterskillfocus", Predicate: "accessible"},
 		{FamilyKey: "weaponfocus", Dataset: "baseitems", Column: "WeaponFocusFeat"},
 		{FamilyKey: "weaponspecialization", Dataset: "baseitems", Column: "WeaponSpecializationFeat"},
 		{FamilyKey: "improvedcritical", Dataset: "baseitems", Column: "WeaponImprovedCriticalFeat"},
@@ -1882,7 +1884,7 @@ func validateGeneratedFeatFamilies(dataDir string, report *ValidationReport) {
 		if !ok {
 			continue
 		}
-		if spec.ChildSource.Dataset != requirement.Dataset ||
+		if (requirement.Dataset != "" && spec.ChildSource.Dataset != requirement.Dataset) ||
 			spec.ChildSource.Column != requirement.Column ||
 			spec.ChildSource.Predicate != requirement.Predicate {
 			report.Diagnostics = append(report.Diagnostics, Diagnostic{
@@ -2081,7 +2083,10 @@ func validateGeneratedFeatFamilyCompleteness(path string, spec familyExpansionSp
 		}
 		if include {
 			if familyAllowlist {
-				slug := strings.TrimPrefix(sourceKey, spec.ChildSource.Dataset+":")
+				slug := sourceKey
+				if idx := strings.Index(slug, ":"); idx >= 0 {
+					slug = slug[idx+1:]
+				}
 				featKey, _, _, err := ctx.resolveGeneratedFeatIdentity(spec, slug, row)
 				if err != nil {
 					report.Diagnostics = append(report.Diagnostics, Diagnostic{