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.Runtime.Tests/ScriptedAlarms/ScriptedAlarmStatePersistenceTests.cs

@@ -13,6 +13,7 @@ namespace ZB.MOM.WW.OtOpcUa.Runtime.Tests.ScriptedAlarms;
 public sealed class ScriptedAlarmStatePersistenceTests : RuntimeActorTestBase
 {
     /// <summary>Verifies that alarm state transitions write to the state store with the correct lastAckUser value.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Transition_writes_to_state_store_with_lastAckUser()
     {
@@ -39,6 +40,7 @@ public sealed class ScriptedAlarmStatePersistenceTests : RuntimeActorTestBase
     }
 
     /// <summary>Verifies that actor restart restores persisted state so pending acknowledgment is not dropped.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task PreStart_restores_persisted_state_so_restart_does_not_drop_pending_ack()
     {
@@ -64,6 +66,7 @@ public sealed class ScriptedAlarmStatePersistenceTests : RuntimeActorTestBase
     }
 
     /// <summary>Verifies that alarm boots to inactive state when no persisted state exists.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task PreStart_with_no_persisted_state_boots_inactive()
     {
@@ -80,6 +83,7 @@ public sealed class ScriptedAlarmStatePersistenceTests : RuntimeActorTestBase
     }
 
     /// <summary>Verifies that EF-based alarm actor state store correctly persists and restores state through the config database.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task EfAlarmActorStateStore_round_trip_persists_via_ConfigDb()
     {
@@ -118,6 +122,7 @@ public sealed class ScriptedAlarmStatePersistenceTests : RuntimeActorTestBase
     }
 
     /// <summary>Verifies that loading an alarm state for a missing ID returns null.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task EfAlarmActorStateStore_load_for_missing_id_returns_null()
     {
@@ -136,17 +141,11 @@ public sealed class ScriptedAlarmStatePersistenceTests : RuntimeActorTestBase
         /// <summary>Gets all saved alarm state snapshots in order.</summary>
         public List<AlarmActorStateSnapshot> Snapshots => _saves.ToList();
 
-        /// <summary>Loads the alarm state snapshot for the specified alarm ID.</summary>
-        /// <param name="alarmId">The alarm ID.</param>
-        /// <param name="ct">The cancellation token.</param>
-        /// <returns>The alarm state snapshot if found, null otherwise.</returns>
+        /// <inheritdoc />
         public Task<AlarmActorStateSnapshot?> LoadAsync(string alarmId, CancellationToken ct)
             => Task.FromResult(_byId.TryGetValue(alarmId, out var v) ? v : null);
 
-        /// <summary>Saves the alarm state snapshot.</summary>
-        /// <param name="snapshot">The alarm state snapshot to save.</param>
-        /// <param name="ct">The cancellation token.</param>
-        /// <returns>A completed task.</returns>
+        /// <inheritdoc />
         public Task SaveAsync(AlarmActorStateSnapshot snapshot, CancellationToken ct)
         {
             _byId[snapshot.AlarmId] = snapshot;