docs(src): add missing XML docs and strip tracking-ID comments

Sweep of 203 source files resolving CommentChecker findings: add
<summary>/<param>/<returns>/<inheritdoc> where missing, and remove
resolved task/issue tracking markers (Tests-NNN, Worker-NNN, Server-NNN,
Task N) from code comments. Comment/doc-only — no logic changes.
Server+Tests build clean under TreatWarningsAsErrors.

src/ZB.MOM.WW.MxGateway.Tests/Gateway/Workers/WorkerFrameProtocolTests.cs

@@ -11,6 +11,7 @@ public sealed class WorkerFrameProtocolTests
     private const string SessionId = "session-1";
 
     /// <summary>Verifies that writing and reading a valid envelope round-trips the frame correctly.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task WriteAndReadAsync_WithValidEnvelope_RoundTripsFrame()
     {
@@ -29,6 +30,7 @@ public sealed class WorkerFrameProtocolTests
     }
 
     /// <summary>Verifies that reading a frame with partial reads reassembles the frame correctly.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ReadAsync_WithPartialReads_ReassemblesFrame()
     {
@@ -45,6 +47,7 @@ public sealed class WorkerFrameProtocolTests
     }
 
     /// <summary>Verifies that reading a frame with zero length throws a malformed length exception.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ReadAsync_WithZeroLengthFrame_ThrowsMalformedLength()
     {
@@ -60,6 +63,7 @@ public sealed class WorkerFrameProtocolTests
     }
 
     /// <summary>Verifies that reading a frame with oversized length throws before allocating the payload.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ReadAsync_WithOversizedLength_ThrowsBeforePayloadAllocation()
     {
@@ -77,6 +81,7 @@ public sealed class WorkerFrameProtocolTests
     }
 
     /// <summary>Verifies that reading a frame with wrong protocol version throws a protocol version mismatch exception.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ReadAsync_WithWrongProtocolVersion_ThrowsProtocolVersionMismatch()
     {
@@ -94,6 +99,7 @@ public sealed class WorkerFrameProtocolTests
     }
 
     /// <summary>Verifies that reading a frame with wrong session ID throws a session mismatch exception.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ReadAsync_WithWrongSessionId_ThrowsSessionMismatch()
     {
@@ -111,6 +117,7 @@ public sealed class WorkerFrameProtocolTests
     }
 
     /// <summary>Verifies that reading a frame with malformed payload throws an invalid envelope exception.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ReadAsync_WithMalformedPayload_ThrowsInvalidEnvelope()
     {
@@ -127,6 +134,7 @@ public sealed class WorkerFrameProtocolTests
     }
 
     /// <summary>Verifies that reading a frame with missing envelope body throws an invalid envelope exception.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ReadAsync_WithMissingEnvelopeBody_ThrowsInvalidEnvelope()
     {
@@ -144,6 +152,7 @@ public sealed class WorkerFrameProtocolTests
     }
 
     /// <summary>Verifies that writing an oversized envelope throws a message too large exception.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task WriteAsync_WithOversizedEnvelope_ThrowsMessageTooLarge()
     {