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/Core/ZB.MOM.WW.OtOpcUa.Configuration.Tests/DriverHostStatusTests.cs

@@ -17,6 +17,7 @@ namespace ZB.MOM.WW.OtOpcUa.Configuration.Tests;
 public sealed class DriverHostStatusTests(SchemaComplianceFixture fixture)
 {
     /// <summary>Verifies that the composite key allows the same host across different nodes or drivers.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Composite_key_allows_same_host_across_different_nodes_or_drivers()
     {
@@ -58,6 +59,7 @@ public sealed class DriverHostStatusTests(SchemaComplianceFixture fixture)
     }
 
     /// <summary>Verifies that the upsert pattern updates existing records in place.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Upsert_pattern_for_same_key_updates_in_place()
     {
@@ -97,6 +99,7 @@ public sealed class DriverHostStatusTests(SchemaComplianceFixture fixture)
     }
 
     /// <summary>Verifies that the State enum is persisted as a string, not an integer.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Enum_persists_as_string_not_int()
     {