Integrate configuration searches into engine loading

internal/engine/options.go

@@ -31,6 +31,16 @@ func selectOptions[T any](source Source, supplied []Options[T]) (Options[T], []D
 	if options.Filesystem != nil {
 		diagnostics = append(diagnostics, filesystemOptionDiagnostics(source, options.Filesystem)...)
 	}
+	if source.kind == sourceSearch {
+		for _, issue := range source.searchIssues {
+			diagnostics = append(diagnostics, optionDiagnostic(CodeOptionsInvalid, issue))
+		}
+		if source.search == nil {
+			diagnostics = append(diagnostics, optionDiagnostic(CodeOptionsInvalid, "configuration search is invalid"))
+		} else {
+			diagnostics = append(diagnostics, validateSearch(*source.search, source.searchApp)...)
+		}
+	}
 	if source.kind == sourceNone && activeOverlay(options.Overlay) && options.Filesystem == nil {
 		diagnostics = append(diagnostics, optionDiagnostic(CodeOptionsInvalid, "NoSource overlays require explicit filesystem context"))
 	}