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/GalaxyDriverAlarmEventArgsExtensionTests.cs

@@ -17,6 +17,7 @@ public sealed class GalaxyDriverAlarmEventArgsExtensionTests
     /// <summary>
     /// Verifies that acknowledge transition with full payload populates extended fields.
     /// </summary>
+    /// <returns>A task that represents the asynchronous test operation.</returns>
     [Fact]
     public async Task Acknowledge_transition_with_full_payload_populates_extended_fields()
     {
@@ -53,6 +54,7 @@ public sealed class GalaxyDriverAlarmEventArgsExtensionTests
     /// <summary>
     /// Verifies that raise transition without optional fields leaves them null.
     /// </summary>
+    /// <returns>A task that represents the asynchronous test operation.</returns>
     [Fact]
     public async Task Raise_transition_without_optional_fields_leaves_them_null()
     {
@@ -118,9 +120,8 @@ public sealed class GalaxyDriverAlarmEventArgsExtensionTests
         public void Emit(GalaxyAlarmTransition transition)
             => OnAlarmTransition?.Invoke(this, transition);
 
-        /// <summary>
-        /// Disposes the alarm feed asynchronously.
-        /// </summary>
+        /// <summary>Disposes the alarm feed asynchronously.</summary>
+        /// <returns>A completed value task.</returns>
         public ValueTask DisposeAsync() => ValueTask.CompletedTask;
     }
 }