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/Core/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms.Tests/ScriptedAlarmSourceTests.cs

@@ -41,6 +41,7 @@ public sealed class ScriptedAlarmSourceTests
     }
 
     /// <summary>Verifies that subscribing with an empty filter receives every alarm emission.</summary>
+    /// <returns>A task that represents the asynchronous test.</returns>
     [Fact]
     public async Task Subscribe_with_empty_filter_receives_every_alarm_emission()
     {
@@ -66,6 +67,7 @@ public sealed class ScriptedAlarmSourceTests
     }
 
     /// <summary>Verifies that subscribing with an equipment prefix filters alarms by that prefix.</summary>
+    /// <returns>A task that represents the asynchronous test.</returns>
     [Fact]
     public async Task Subscribe_with_equipment_prefix_filters_by_that_prefix()
     {
@@ -89,6 +91,7 @@ public sealed class ScriptedAlarmSourceTests
     }
 
     /// <summary>Verifies that unsubscribing stops further alarm events.</summary>
+    /// <returns>A task that represents the asynchronous test.</returns>
     [Fact]
     public async Task Unsubscribe_stops_further_events()
     {
@@ -108,6 +111,7 @@ public sealed class ScriptedAlarmSourceTests
     }
 
     /// <summary>Verifies that AcknowledgeAsync routes to the engine with a default user.</summary>
+    /// <returns>A task that represents the asynchronous test.</returns>
     [Fact]
     public async Task AcknowledgeAsync_routes_to_engine_with_default_user()
     {
@@ -130,6 +134,7 @@ public sealed class ScriptedAlarmSourceTests
     }
 
     /// <summary>Verifies that null arguments are rejected.</summary>
+    /// <returns>A task that represents the asynchronous test.</returns>
     [Fact]
     public async Task Null_arguments_rejected()
     {