docs: backfill XML documentation across 756 files

Adds <summary>, <param>, <typeparam>, and <inheritdoc/> tags to public
members surfaced by commentchecker — resolves 5,847 of 5,869 issues
(99.6%) across three /fixdocs passes.

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Tests/AbLegacyHostAndStatusTests.cs

@@ -8,6 +8,11 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Tests;
 [Trait("Category", "Unit")]
 public sealed class AbLegacyHostAndStatusTests
 {
+    /// <summary>Verifies that HostAddress parses valid URI strings correctly.</summary>
+    /// <param name="input">The raw URI string to parse.</param>
+    /// <param name="gateway">The expected gateway host.</param>
+    /// <param name="port">The expected port number.</param>
+    /// <param name="path">The expected CIP path component.</param>
     [Theory]
     [InlineData("ab://10.0.0.5/1,0", "10.0.0.5", 44818, "1,0")]
     [InlineData("ab://10.0.0.5/", "10.0.0.5", 44818, "")]
@@ -22,6 +27,8 @@ public sealed class AbLegacyHostAndStatusTests
         parsed.CipPath.ShouldBe(path);
     }
 
+    /// <summary>Verifies that HostAddress rejects invalid URI strings.</summary>
+    /// <param name="input">The invalid or null URI string to test.</param>
     [Theory]
     [InlineData(null)]
     [InlineData("http://10.0.0.5/1,0")]
@@ -33,6 +40,7 @@ public sealed class AbLegacyHostAndStatusTests
         AbLegacyHostAddress.TryParse(input).ShouldBeNull();
     }
 
+    /// <summary>Verifies that HostAddress.ToString produces canonical URI format.</summary>
     [Fact]
     public void HostAddress_ToString_canonicalises()
     {
@@ -40,6 +48,9 @@ public sealed class AbLegacyHostAndStatusTests
         new AbLegacyHostAddress("10.0.0.5", 2222, "1,0").ToString().ShouldBe("ab://10.0.0.5:2222/1,0");
     }
 
+    /// <summary>Verifies that PCCC status codes are mapped to OPC UA status codes correctly.</summary>
+    /// <param name="sts">The PCCC status byte to map.</param>
+    /// <param name="expected">The expected OPC UA status code.</param>
     [Theory]
     [InlineData((byte)0x00, AbLegacyStatusMapper.Good)]
     [InlineData((byte)0x10, AbLegacyStatusMapper.BadNotSupported)]
@@ -54,6 +65,9 @@ public sealed class AbLegacyHostAndStatusTests
         AbLegacyStatusMapper.MapPcccStatus(sts).ShouldBe(expected);
     }
 
+    /// <summary>Verifies that libplctag Status enum members are mapped to OPC UA status codes correctly.</summary>
+    /// <param name="status">The libplctag Status enum value to map.</param>
+    /// <param name="expected">The expected OPC UA status code.</param>
     // Driver.AbLegacy-010 — tests use the libplctag.NET Status enum members (what
     // (int)Tag.GetStatus() actually returns) rather than the unverified magic integers
     // that predated this fix (-5/-7/-14/-16/-17 matched neither native PLCTAG_ERR_*
@@ -78,6 +92,7 @@ public sealed class AbLegacyHostAndStatusTests
         AbLegacyStatusMapper.MapLibplctagStatus((int)status).ShouldBe(expected);
     }
 
+    /// <summary>Verifies that timeout errors are distinguished from generic communication errors.</summary>
     [Fact]
     public void MapLibplctagStatus_distinguishes_timeout_from_generic_comms_error()
     {