fix: remove dead DirectoryLineSelected join; fix SelfviewPositionFb description

DirectoryLineSelected (digital 101, FromSIMPL) had no handler anywhere in
VideoCodecBase.cs — directory selection is driven by analog 101
(DirectorySelectRow). DirectoryEntryIsContact (ToSIMPL) already documents
the output side of that join. Removed the dead inbound entry.

SelfviewPositionFb (serial 211) description "advance selfview position"
read like a command; updated to "Current selfview PIP position string FB"
to accurately reflect that it is a ToSIMPL feedback.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/PepperDash.Essentials.Core/Bridges/JoinMaps/VideoCodecControllerJoinMap.cs

@@ -442,22 +442,6 @@ namespace PepperDash.Essentials.Core.Bridges.JoinMaps;
 				JoinType = eJoinType.Digital
 			});
 
-		/// <summary>
-		/// Directory Line Selected
-		/// </summary>
-		[JoinName("DirectoryLineSelected")]
-		public JoinDataComplete DirectoryLineSelected = new JoinDataComplete(
-			new JoinData
-			{
-				JoinNumber = 101,
-				JoinSpan = 1
-			},
-			new JoinMetadata
-			{
-				Description = "Directory Line Selected FB",
-				JoinCapabilities = eJoinCapabilities.FromSIMPL,
-				JoinType = eJoinType.Digital
-			});
 
 		/// <summary>
 		/// Directory Is Root
@@ -1873,7 +1857,7 @@ namespace PepperDash.Essentials.Core.Bridges.JoinMaps;
 			},
 			new JoinMetadata
 			{
-				Description = "advance selfview position",
+				Description = "Current selfview PIP position string FB",
 				JoinCapabilities = eJoinCapabilities.ToSIMPL,
 				JoinType = eJoinType.Serial
 			});