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/FocasDriverMediumFindingsTests.cs

@@ -20,6 +20,7 @@ public sealed class FocasDriverMediumFindingsTests
 {
     // ---- Driver.FOCAS-003: unknown DeviceHostAddress fails at InitializeAsync ----
 
+    /// <summary>Verifies that initialization throws when a tag references an undeclared device.</summary>
     [Fact]
     public async Task InitializeAsync_throws_when_tag_DeviceHostAddress_not_in_Devices()
     {
@@ -41,6 +42,7 @@ public sealed class FocasDriverMediumFindingsTests
         ex.Message.ShouldContain("not in the Devices list");
     }
 
+    /// <summary>Verifies that initialization errors name the offending tag.</summary>
     [Fact]
     public async Task InitializeAsync_throws_naming_the_offending_tag()
     {
@@ -61,6 +63,7 @@ public sealed class FocasDriverMediumFindingsTests
         ex.Message.ShouldContain("TypoTag");
     }
 
+    /// <summary>Verifies that initialization succeeds when all tags reference declared devices.</summary>
     [Fact]
     public async Task InitializeAsync_succeeds_when_all_tags_reference_declared_devices()
     {
@@ -86,6 +89,7 @@ public sealed class FocasDriverMediumFindingsTests
 
     // ---- Driver.FOCAS-004: all FOCAS user tags advertised as ViewOnly ----
 
+    /// <summary>Verifies that all user tags are advertised as ViewOnly regardless of Writable setting.</summary>
     [Fact]
     public async Task DiscoverAsync_all_user_tags_are_ViewOnly_regardless_of_Writable_field()
     {
@@ -114,6 +118,7 @@ public sealed class FocasDriverMediumFindingsTests
 
     // ---- Driver.FOCAS-005: Volatile-guarded _health survives concurrent reads ----
 
+    /// <summary>Verifies that GetHealth reflects state updated from concurrent reads.</summary>
     [Fact]
     public async Task GetHealth_reflects_state_updated_from_concurrent_reads()
     {
@@ -142,6 +147,7 @@ public sealed class FocasDriverMediumFindingsTests
 
     // ---- Driver.FOCAS-006: EnsureConnectedAsync recreates a disposed/stale client ----
 
+    /// <summary>Verifies that reads recover after client is externally disposed.</summary>
     [Fact]
     public async Task Read_recovers_after_client_is_externally_disposed()
     {
@@ -177,6 +183,7 @@ public sealed class FocasDriverMediumFindingsTests
         factory.Clients[1].ConnectCount.ShouldBe(1);
     }
 
+    /// <summary>Verifies that reads dispose stale clients before creating fresh ones.</summary>
     [Fact]
     public async Task Read_disposes_stale_client_before_creating_fresh_one()
     {
@@ -211,6 +218,7 @@ public sealed class FocasDriverMediumFindingsTests
 
     // ---- Driver.FOCAS-012: factory round-trip for all three opt-in sections ----
 
+    /// <summary>Verifies factory round-trip with all optional configuration sections.</summary>
     [Fact]
     public void CreateInstance_full_round_trip_all_opt_in_sections()
     {
@@ -240,24 +248,51 @@ public sealed class FocasDriverMediumFindingsTests
 
     // ---- helpers ----
 
+    /// <summary>Records folder and variable additions for test verification.</summary>
     private sealed class RecordingBuilder : IAddressSpaceBuilder
     {
+        /// <summary>Gets or sets the list of added variables.</summary>
         public List<(string BrowseName, DriverAttributeInfo Info)> Variables { get; } = new();
+
+        /// <summary>Gets or sets the list of added folders.</summary>
         public List<(string BrowseName, string DisplayName)> Folders { get; } = new();
 
+        /// <summary>Records a folder and returns this builder for chaining.</summary>
+        /// <param name="browseName">The OPC UA browse name for the folder.</param>
+        /// <param name="displayName">The display name for the folder.</param>
         public IAddressSpaceBuilder Folder(string browseName, string displayName)
         { Folders.Add((browseName, displayName)); return this; }
 
+        /// <summary>Records a variable and returns a handle for it.</summary>
+        /// <param name="browseName">The OPC UA browse name for the variable.</param>
+        /// <param name="displayName">The display name for the variable.</param>
+        /// <param name="info">The driver attribute information for the variable.</param>
         public IVariableHandle Variable(string browseName, string displayName, DriverAttributeInfo info)
         { Variables.Add((browseName, info)); return new Handle(info.FullName); }
 
+        /// <summary>No-op property addition for test compatibility.</summary>
+        /// <param name="_">The property name (unused).</param>
+        /// <param name="__">The property data type (unused).</param>
+        /// <param name="___">The property value (unused).</param>
         public void AddProperty(string _, DriverDataType __, object? ___) { }
 
+        /// <summary>Test variable handle implementation.</summary>
         private sealed class Handle(string fullRef) : IVariableHandle
         {
+            /// <summary>Gets the full reference path of this variable.</summary>
             public string FullReference => fullRef;
+
+            /// <summary>Marks this variable as an alarm condition and returns a sink for it.</summary>
+            /// <param name="info">The alarm condition information.</param>
             public IAlarmConditionSink MarkAsAlarmCondition(AlarmConditionInfo info) => new NullSink();
         }
-        private sealed class NullSink : IAlarmConditionSink { public void OnTransition(AlarmEventArgs args) { } }
+
+        /// <summary>No-op alarm condition sink for testing.</summary>
+        private sealed class NullSink : IAlarmConditionSink
+        {
+            /// <summary>Handles alarm condition transitions (no-op for testing).</summary>
+            /// <param name="args">The alarm event arguments.</param>
+            public void OnTransition(AlarmEventArgs args) { }
+        }
     }
 }