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.FOCAS.Tests/FocasAlarmProjectionTests.cs

@@ -26,6 +26,7 @@ public sealed class FocasAlarmProjectionTests
         return (drv, factory);
     }
 
+    /// <summary>Verifies that subscribe without enable throws NotSupported.</summary>
     [Fact]
     public async Task Subscribe_without_Enable_throws_NotSupported()
     {
@@ -36,6 +37,7 @@ public sealed class FocasAlarmProjectionTests
             drv.SubscribeAlarmsAsync([], CancellationToken.None));
     }
 
+    /// <summary>Verifies that raise then clear emits both events.</summary>
     [Fact]
     public async Task Raise_then_clear_emits_both_events()
     {
@@ -67,6 +69,7 @@ public sealed class FocasAlarmProjectionTests
         events[0].SourceNodeId.ShouldBe(Host);
     }
 
+    /// <summary>Verifies that tick diffs raises and clears without polling loop.</summary>
     [Fact]
     public async Task Tick_diffs_raises_and_clears_without_polling_loop()
     {
@@ -111,6 +114,7 @@ public sealed class FocasAlarmProjectionTests
         events[0].AlarmType.ShouldBe("Parameter");
     }
 
+    /// <summary>Verifies that severity mapping matches docs.</summary>
     [Fact]
     public void Severity_mapping_matches_docs()
     {