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.FOCAS.IntegrationTests/Series/WireBackendTests.cs

@@ -29,6 +29,7 @@ public sealed class WireBackendTests
     private const string DeviceHost = "focas://127.0.0.1:8193";
 
     /// <summary>Verifies that identity axes and dynamic data populate via the wire backend.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Identity_axes_and_dynamic_populate_via_wire_backend()
     {
@@ -86,6 +87,7 @@ public sealed class WireBackendTests
     }
 
     /// <summary>Verifies that program and operation mode data populate via the wire backend.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Program_and_operation_mode_populate_via_wire_backend()
     {
@@ -151,6 +153,7 @@ public sealed class WireBackendTests
     }
 
     /// <summary>Verifies that timer data populates via the wire backend.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Timers_populate_via_wire_backend()
     {
@@ -209,6 +212,7 @@ public sealed class WireBackendTests
     }
 
     /// <summary>Verifies that spindle load and max RPM data populate via the wire backend.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Spindle_load_and_max_rpm_populate_via_wire_backend()
     {