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.AbCip.Tests/AbCipPerDeviceConnectionOptionsTests.cs

@@ -21,6 +21,7 @@ public sealed class AbCipPerDeviceConnectionOptionsTests
     private const string Device = "ab://10.0.0.5/1,0";
 
     /// <summary>Verifies that per-device AllowPacking override is forwarded to tag creation parameters.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Device_AllowPacking_override_is_forwarded_to_tag_create_params()
     {
@@ -40,6 +41,7 @@ public sealed class AbCipPerDeviceConnectionOptionsTests
     }
 
     /// <summary>Verifies that AllowPacking defaults inherit from the family profile when not overridden.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Device_AllowPacking_default_inherits_from_family_profile()
     {
@@ -61,6 +63,7 @@ public sealed class AbCipPerDeviceConnectionOptionsTests
     }
 
     /// <summary>Verifies that Micro800 devices have AllowPacking defaulting to false from the family profile.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Micro800_default_AllowPacking_is_false_from_family_profile()
     {
@@ -81,6 +84,7 @@ public sealed class AbCipPerDeviceConnectionOptionsTests
     }
 
     /// <summary>Verifies that per-device ConnectionSize override is forwarded to tag creation parameters.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Device_ConnectionSize_override_is_forwarded_to_tag_create_params()
     {
@@ -99,6 +103,7 @@ public sealed class AbCipPerDeviceConnectionOptionsTests
     }
 
     /// <summary>Verifies that ConnectionSize defaults inherit from the family profile when not overridden.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Device_ConnectionSize_default_inherits_from_family_profile()
     {