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.Worker.Tests/Ipc/WorkerFrameProtocolTests.cs

@@ -14,6 +14,7 @@ public sealed class WorkerFrameProtocolTests
     private const string Nonce = "nonce-secret";
 
     /// <summary>Verifies that valid envelopes round-trip through write and read.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task WriteAndReadAsync_WithValidEnvelope_RoundTripsFrame()
     {
@@ -32,6 +33,7 @@ public sealed class WorkerFrameProtocolTests
     }
 
     /// <summary>Verifies that wrong protocol version throws mismatch error.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ReadAsync_WithWrongProtocolVersion_ThrowsProtocolVersionMismatch()
     {
@@ -49,6 +51,7 @@ public sealed class WorkerFrameProtocolTests
     }
 
     /// <summary>Verifies that wrong session ID throws mismatch error.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ReadAsync_WithWrongSessionId_ThrowsSessionMismatch()
     {
@@ -72,6 +75,7 @@ public sealed class WorkerFrameProtocolTests
     /// length prefix is the leading four bytes of the stream, so a four-zero-byte
     /// stream is exactly a frame declaring a zero-length payload.
     /// </summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ReadAsync_WithZeroLengthPayload_ThrowsMalformedLength()
     {
@@ -93,6 +97,7 @@ public sealed class WorkerFrameProtocolTests
     /// A small maximum is configured so the rejection is asserted without
     /// allocating a multi-megabyte buffer.
     /// </summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ReadAsync_WithPayloadAboveConfiguredMaximum_ThrowsMessageTooLarge()
     {
@@ -115,6 +120,7 @@ public sealed class WorkerFrameProtocolTests
     }
 
     /// <summary>Verifies that malformed payload throws invalid envelope error.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ReadAsync_WithMalformedPayload_ThrowsInvalidEnvelope()
     {
@@ -130,7 +136,7 @@ public sealed class WorkerFrameProtocolTests
     }
 
     /// <summary>
-    ///     Worker.Tests-021 (a): pins the <c>EndOfStream</c> branch of
+    ///     Pins the <c>EndOfStream</c> branch of
     ///     <c>WorkerFrameReader.ReadExactlyOrThrowAsync</c>. The gateway
     ///     closing its end of the pipe during a partial-frame read is the
     ///     most common production transport failure; the reader must
@@ -140,6 +146,7 @@ public sealed class WorkerFrameProtocolTests
     ///     payload but only supplies 50 bytes, so the inner read loop sees
     ///     <c>bytesRead == 0</c> mid-frame.
     /// </summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ReadAsync_WhenStreamEndsMidFrame_ThrowsEndOfStream()
     {
@@ -157,16 +164,16 @@ public sealed class WorkerFrameProtocolTests
     }
 
     /// <summary>
-    ///     Worker.Tests-021 (b): pins the writer-side
-    ///     <c>MessageTooLarge</c> branch. A session that constructs an
-    ///     envelope whose serialised size exceeds <c>MaxMessageBytes</c>
-    ///     must be rejected by the writer before any bytes are sent down
-    ///     the pipe, so a misbehaving producer cannot push the receiver
-    ///     past its bounds. A small <c>MaxMessageBytes</c> is configured
-    ///     so a modest <c>GatewayHello</c> payload — with its nonce
-    ///     padded out to several hundred bytes — exceeds the limit
+    ///     Pins the writer-side <c>MessageTooLarge</c> branch. A session that
+    ///     constructs an envelope whose serialised size exceeds
+    ///     <c>MaxMessageBytes</c> must be rejected by the writer before any
+    ///     bytes are sent down the pipe, so a misbehaving producer cannot
+    ///     push the receiver past its bounds. A small <c>MaxMessageBytes</c>
+    ///     is configured so a modest <c>GatewayHello</c> payload — with its
+    ///     nonce padded out to several hundred bytes — exceeds the limit
     ///     without allocating anything large.
     /// </summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task WriteAsync_WithEnvelopeAboveConfiguredMaximum_ThrowsMessageTooLarge()
     {
@@ -191,11 +198,10 @@ public sealed class WorkerFrameProtocolTests
     }
 
     /// <summary>
-    ///     Worker.Tests-021 (c): documents that the writer-side
-    ///     <c>InvalidEnvelope</c> branch (raised when
-    ///     <c>WorkerEnvelope.CalculateSize()</c> returns 0) is unreachable
-    ///     through public API. <c>WorkerEnvelopeValidator.Validate</c> (run
-    ///     before the size check in <c>WorkerFrameWriter.WriteAsync</c>)
+    ///     Documents that the writer-side <c>InvalidEnvelope</c> branch
+    ///     (raised when <c>WorkerEnvelope.CalculateSize()</c> returns 0) is
+    ///     unreachable through public API. <c>WorkerEnvelopeValidator.Validate</c>
+    ///     (run before the size check in <c>WorkerFrameWriter.WriteAsync</c>)
     ///     rejects any envelope whose <c>BodyCase</c> is <c>None</c> with
     ///     <c>InvalidEnvelope</c>; a body-less envelope is therefore
     ///     intercepted before the empty-payload branch can fire. Any
@@ -209,6 +215,7 @@ public sealed class WorkerFrameProtocolTests
     ///     would weaken the writer against future serialisation
     ///     regressions; this test makes its rationale visible.
     /// </summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task WriteAsync_WithEmptyEnvelope_ThrowsInvalidEnvelopeFromValidator()
     {
@@ -233,6 +240,7 @@ public sealed class WorkerFrameProtocolTests
     }
 
     /// <summary>Verifies that concurrent writes produce complete serialized frames.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task WriteAsync_WithConcurrentCalls_SerializesCompleteFrames()
     {
@@ -256,12 +264,13 @@ public sealed class WorkerFrameProtocolTests
     }
 
     /// <summary>
-    /// Worker-009 regression: the reader rents its payload buffer from a
-    /// shared pool, so a rented buffer can be larger than the current frame
-    /// and may carry bytes from a previous, larger frame. Reading frames of
-    /// differing sizes back-to-back through one reader must parse each frame
-    /// using only its own payload length, never trailing pooled bytes.
+    /// The reader rents its payload buffer from a shared pool, so a rented
+    /// buffer can be larger than the current frame and may carry bytes from
+    /// a previous, larger frame. Reading frames of differing sizes
+    /// back-to-back through one reader must parse each frame using only its
+    /// own payload length, never trailing pooled bytes.
     /// </summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ReadAsync_WithVaryingFrameSizes_ParsesEachFrameExactly()
     {