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.Modbus.Tests/ModbusCapTests.cs

@@ -55,11 +55,13 @@ public sealed class ModbusCapTests
             return Task.FromException<byte[]>(new ModbusException(fc, 0x01, $"fc={fc} unsupported"));
         }
 
-        /// <inheritdoc />
+        /// <summary>Releases resources used by this transport instance.</summary>
+        /// <returns>A completed value task.</returns>
         public ValueTask DisposeAsync() => ValueTask.CompletedTask;
     }
 
     /// <summary>Verifies that a read within the cap issues a single FC03 request.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Read_within_cap_issues_single_FC03_request()
     {
@@ -77,6 +79,7 @@ public sealed class ModbusCapTests
     }
 
     /// <summary>Verifies that a read above cap splits into two FC03 requests.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Read_above_cap_splits_into_two_FC03_requests()
     {
@@ -112,6 +115,7 @@ public sealed class ModbusCapTests
     }
 
     /// <summary>Verifies that read cap honors Mitsubishi lower cap of 64 registers.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Read_cap_honors_Mitsubishi_lower_cap_of_64()
     {
@@ -131,6 +135,7 @@ public sealed class ModbusCapTests
     }
 
     /// <summary>Verifies that write exceeding cap throws instead of splitting.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Write_exceeding_cap_throws_instead_of_splitting()
     {
@@ -155,6 +160,7 @@ public sealed class ModbusCapTests
     }
 
     /// <summary>Verifies that write within cap proceeds normally.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Write_within_cap_proceeds_normally()
     {