docs: complete XML doc comments via fixdocs (2757 to 131 findings)

Add missing <returns>/<param>/<summary>/<typeparam> tags and clean up
misused inheritdoc across 481 files so the documented API surface is
complete. Documentation-only (zero code lines changed). The 131 remaining
findings are inheritdoc-style warnings deliberately left to preserve
hand-written implementation rationale (plan-decision notes, race-condition
explanations).

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests/Runtime/EventPumpStreamFaultTests.cs

@@ -19,6 +19,7 @@ public sealed class EventPumpStreamFaultTests
     private const int WaitMs = 2_000;
 
     /// <summary>Verifies that stream fault invokes the callback with the exception.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task StreamFault_InvokesOnStreamFaultCallback_WithTheCause()
     {
@@ -42,6 +43,7 @@ public sealed class EventPumpStreamFaultTests
     }
 
     /// <summary>Verifies that stream fault drives the reconnect supervisor through reopen and replay.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task StreamFault_DrivesReconnectSupervisorReopenReplay()
     {
@@ -79,6 +81,7 @@ public sealed class EventPumpStreamFaultTests
     }
 
     /// <summary>Verifies that a faulted pump cannot be restarted in place, but a fresh pump resumes dispatch.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task FaultedPump_IsNotRestartableInPlace_ButAFreshPumpResumesDispatch()
     {
@@ -122,6 +125,7 @@ public sealed class EventPumpStreamFaultTests
     }
 
     /// <summary>Verifies that clean shutdown does not invoke the stream fault callback.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task CleanShutdown_DoesNotInvokeOnStreamFault()
     {
@@ -150,22 +154,16 @@ public sealed class EventPumpStreamFaultTests
         private readonly Channel<MxEvent> _stream =
             Channel.CreateUnbounded<MxEvent>(new UnboundedChannelOptions { SingleReader = true });
 
-        /// <summary>Subscribes to multiple tags (test stub).</summary>
-        /// <param name="fullReferences">The tag references to subscribe to.</param>
-        /// <param name="bufferedUpdateIntervalMs">The buffered update interval in milliseconds.</param>
-        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <inheritdoc />
         public Task<IReadOnlyList<SubscribeResult>> SubscribeBulkAsync(
             IReadOnlyList<string> fullReferences, int bufferedUpdateIntervalMs, CancellationToken cancellationToken)
             => Task.FromResult<IReadOnlyList<SubscribeResult>>([]);
 
-        /// <summary>Unsubscribes from multiple tags (test stub).</summary>
-        /// <param name="itemHandles">The item handles to unsubscribe from.</param>
-        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <inheritdoc />
         public Task UnsubscribeBulkAsync(IReadOnlyList<int> itemHandles, CancellationToken cancellationToken)
             => Task.CompletedTask;
 
-        /// <summary>Streams events asynchronously (test stub).</summary>
-        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <inheritdoc />
         public IAsyncEnumerable<MxEvent> StreamEventsAsync(CancellationToken cancellationToken)
             => _stream.Reader.ReadAllAsync(cancellationToken);
 
@@ -183,28 +181,23 @@ public sealed class EventPumpStreamFaultTests
         private readonly Channel<MxEvent> _stream =
             Channel.CreateUnbounded<MxEvent>(new UnboundedChannelOptions { SingleReader = true });
 
-        /// <summary>Subscribes to multiple tags (test stub).</summary>
-        /// <param name="fullReferences">The tag references to subscribe to.</param>
-        /// <param name="bufferedUpdateIntervalMs">The buffered update interval in milliseconds.</param>
-        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <inheritdoc />
         public Task<IReadOnlyList<SubscribeResult>> SubscribeBulkAsync(
             IReadOnlyList<string> fullReferences, int bufferedUpdateIntervalMs, CancellationToken cancellationToken)
             => Task.FromResult<IReadOnlyList<SubscribeResult>>([]);
 
-        /// <summary>Unsubscribes from multiple tags (test stub).</summary>
-        /// <param name="itemHandles">The item handles to unsubscribe from.</param>
-        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <inheritdoc />
         public Task UnsubscribeBulkAsync(IReadOnlyList<int> itemHandles, CancellationToken cancellationToken)
             => Task.CompletedTask;
 
-        /// <summary>Streams events asynchronously (test stub).</summary>
-        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <inheritdoc />
         public IAsyncEnumerable<MxEvent> StreamEventsAsync(CancellationToken cancellationToken)
             => _stream.Reader.ReadAllAsync(cancellationToken);
 
         /// <summary>Emits a data change event asynchronously.</summary>
         /// <param name="itemHandle">The item handle for the data change.</param>
         /// <param name="value">The numeric value of the change.</param>
+        /// <returns>A value task that represents the asynchronous operation.</returns>
         public ValueTask EmitAsync(int itemHandle, double value) =>
             _stream.Writer.WriteAsync(new MxEvent
             {