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/AbCipBoolInDIntRmwTests.cs

@@ -19,6 +19,7 @@ public sealed class AbCipBoolInDIntRmwTests
     }
 
     /// <summary>Verifies that bit set reads parent, ORs bit, and writes back.</summary>
+    /// <returns>A task that represents the asynchronous test operation.</returns>
     [Fact]
     public async Task Bit_set_reads_parent_ORs_bit_writes_back()
     {
@@ -50,6 +51,7 @@ public sealed class AbCipBoolInDIntRmwTests
     }
 
     /// <summary>Verifies that bit clear preserves other bits.</summary>
+    /// <returns>A task that represents the asynchronous test operation.</returns>
     [Fact]
     public async Task Bit_clear_preserves_other_bits()
     {
@@ -73,6 +75,7 @@ public sealed class AbCipBoolInDIntRmwTests
     }
 
     /// <summary>Verifies that concurrent bit writes to same parent compose correctly.</summary>
+    /// <returns>A task that represents the asynchronous test operation.</returns>
     [Fact]
     public async Task Concurrent_bit_writes_to_same_parent_compose_correctly()
     {
@@ -98,6 +101,7 @@ public sealed class AbCipBoolInDIntRmwTests
     }
 
     /// <summary>Verifies that bit writes to different parents each get their own runtime.</summary>
+    /// <returns>A task that represents the asynchronous test operation.</returns>
     [Fact]
     public async Task Bit_writes_to_different_parents_each_get_own_runtime()
     {
@@ -125,6 +129,7 @@ public sealed class AbCipBoolInDIntRmwTests
     }
 
     /// <summary>Verifies that repeat bit writes reuse one parent runtime.</summary>
+    /// <returns>A task that represents the asynchronous test operation.</returns>
     [Fact]
     public async Task Repeat_bit_writes_reuse_one_parent_runtime()
     {