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/GatewayGalaxyAlarmFeedTests.cs

@@ -18,6 +18,7 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests.Runtime;
 public sealed class GatewayGalaxyAlarmFeedTests
 {
     /// <summary>Verifies that the feed decodes active alarm snapshots and live transitions.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Decodes_active_alarm_snapshot_then_live_transition()
     {
@@ -70,6 +71,7 @@ public sealed class GatewayGalaxyAlarmFeedTests
     }
 
     /// <summary>Verifies that the feed drops transitions with unspecified kind and empty messages.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Drops_transition_with_unspecified_kind_and_empty_message()
     {
@@ -107,6 +109,7 @@ public sealed class GatewayGalaxyAlarmFeedTests
     }
 
     /// <summary>Verifies that the feed reopens the stream after a transport fault.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Reopens_stream_after_a_transport_fault()
     {