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.Tests/FocasLowFindingsTests.cs

@@ -23,6 +23,7 @@ public sealed class FocasLowFindingsTests
     /// <summary>
     /// Verifies that ReadAsync uses cached FocasAddress when tag definition has a malformed address after init.
     /// </summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ReadAsync_uses_cached_FocasAddress_when_tag_definition_has_a_malformed_address_after_init()
     {
@@ -59,6 +60,7 @@ public sealed class FocasLowFindingsTests
     /// <summary>
     /// Verifies that WriteAsync also uses cached FocasAddress.
     /// </summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task WriteAsync_uses_cached_FocasAddress_too()
     {
@@ -99,6 +101,7 @@ public sealed class FocasLowFindingsTests
     /// <summary>
     /// Verifies that ProbeLoop cancels a slow ProbeAsync at Probe Timeout.
     /// </summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ProbeLoop_cancels_a_slow_ProbeAsync_at_Probe_Timeout()
     {