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/Browsing/FakeBrowseSession.cs

@@ -11,7 +11,7 @@ internal sealed class FakeBrowseSession : IBrowseSession
     /// <inheritdoc />
     public Guid Token { get; } = Guid.NewGuid();
 
-    /// <summary>Mutable so tests can rewind the timestamp into the reaper's eviction window.</summary>
+    /// <inheritdoc />
     public DateTime LastUsedUtc { get; set; } = DateTime.UtcNow;
 
     /// <summary>True once <see cref="DisposeAsync"/> has run to completion.</summary>
@@ -40,7 +40,8 @@ internal sealed class FakeBrowseSession : IBrowseSession
     public Task<IReadOnlyList<AttributeInfo>> AttributesAsync(string nodeId, CancellationToken ct)
         => AttributesHandler?.Invoke(nodeId, ct) ?? Task.FromResult<IReadOnlyList<AttributeInfo>>(Array.Empty<AttributeInfo>());
 
-    /// <inheritdoc />
+    /// <summary>Disposes the fake browse session asynchronously, recording completion or throwing if configured.</summary>
+    /// <returns>A completed value task.</returns>
     public ValueTask DisposeAsync()
     {
         if (ThrowOnDispose) throw new InvalidOperationException("dispose-failed");