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.AbLegacy.Tests/AbLegacyBitRmwTests.cs

@@ -9,6 +9,7 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Tests;
 public sealed class AbLegacyBitRmwTests
 {
     /// <summary>Verifies that setting a bit reads the parent word, ORs the bit, and writes back.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Bit_set_reads_parent_word_ORs_bit_writes_back()
     {
@@ -33,6 +34,7 @@ public sealed class AbLegacyBitRmwTests
     }
 
     /// <summary>Verifies that clearing a bit preserves other bits in the word.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Bit_clear_preserves_other_bits_in_N_file_word()
     {
@@ -54,6 +56,7 @@ public sealed class AbLegacyBitRmwTests
     }
 
     /// <summary>Verifies that concurrent bit writes to the same word compose correctly.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Concurrent_bit_writes_to_same_word_compose_correctly()
     {
@@ -79,6 +82,7 @@ public sealed class AbLegacyBitRmwTests
     }
 
     /// <summary>Verifies that repeated bit writes reuse the parent word runtime.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Repeat_bit_writes_reuse_parent_runtime()
     {