Port SAP B1 V3-style select on expanded entities

Re-apply the GeneXus extension that lets consumers encode column paths
with '~' instead of '/' to opt into V3-style select on expanded entities
(SAP B1 services do not accept V4 nested $select syntax).

The escape is unwound in V4 CommandFormatter.SelectPathSegmentColumns
right before returning, after the column filtering has run with the
V4-style first-segment matching intact.

Original commit: ee78142 'Add support for V3-style select on expanded
entities'.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: claudiamurialdo

src/Simple.OData.Client.V4.Adapter/CommandFormatter.cs

@@ -273,6 +273,12 @@ private static void MergeOrderByColumns(ODataExpandAssociation expandAssociation
 		}
 	}
 
+	// Consumers that need V3-style select on expanded entities (e.g. SAP B1, which
+	// does not accept V4 nested $select syntax) can encode column paths with '~'
+	// instead of '/'. The escape is unwound here so the formatter emits a flat
+	// $select column list containing slashes.
+	private const char ODataV3FormattingEscapeSeparator = '~';
+
 	private IList<string> SelectPathSegmentColumns(
 		IList<string> columns, EntityCollection collection, IList<string> expandedPaths)
 	{
@@ -283,6 +289,7 @@ private IList<string> SelectPathSegmentColumns(
 
 		return columns
 			.Where(x => !expandedNavigationProperties.Any(y => y.Equals(FormatFirstSegment(x), StringComparison.Ordinal)))
+			.Select(x => x.Replace(ODataV3FormattingEscapeSeparator, '/'))
 			.ToList();
 	}