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/Server/ZB.MOM.WW.OtOpcUa.AdminUI.Tests/GalaxyDriverPageFormSerializationTests.cs

@@ -25,6 +25,7 @@ public sealed class GalaxyDriverPageFormSerializationTests
         WriteIndented = false,
     };
 
+    /// <summary>Verifies that a round-trip serialization preserves all known fields of GalaxyDriverOptions.</summary>
     [Fact]
     public void RoundTrip_PreservesKnownFields()
     {
@@ -76,6 +77,7 @@ public sealed class GalaxyDriverPageFormSerializationTests
         back.ProbeTimeoutSeconds.ShouldBe(45);
     }
 
+    /// <summary>Verifies that deserialization silently drops unknown fields from the JSON input.</summary>
     [Fact]
     public void Deserialize_DropsUnknownFields()
     {