docs: complete XML doc coverage (returns, summaries, inheritdoc)

Resolve all 622 issues flagged by the enhanced CommentChecker: add missing
<returns> tags (incl. the standard phrasing on non-generic Task methods),
add missing <summary> tags, and replace misused/redundant <inheritdoc/> on
members that override or implement nothing with real documentation.
Documentation-only — no behavior change; solution builds clean.

src/ZB.MOM.WW.ScadaBridge.DeploymentManager/StateTransitionValidator.cs

@@ -18,21 +18,25 @@ public static class StateTransitionValidator
 {
     /// <summary>Returns true when a deploy operation is allowed from the given state.</summary>
     /// <param name="currentState">The current instance state.</param>
+    /// <returns><see langword="true"/> if deploy is permitted; otherwise <see langword="false"/>.</returns>
     public static bool CanDeploy(InstanceState currentState) =>
         currentState is InstanceState.NotDeployed or InstanceState.Enabled or InstanceState.Disabled;
 
     /// <summary>Returns true when a disable operation is allowed from the given state.</summary>
     /// <param name="currentState">The current instance state.</param>
+    /// <returns><see langword="true"/> if disable is permitted; otherwise <see langword="false"/>.</returns>
     public static bool CanDisable(InstanceState currentState) =>
         currentState == InstanceState.Enabled;
 
     /// <summary>Returns true when an enable operation is allowed from the given state.</summary>
     /// <param name="currentState">The current instance state.</param>
+    /// <returns><see langword="true"/> if enable is permitted; otherwise <see langword="false"/>.</returns>
     public static bool CanEnable(InstanceState currentState) =>
         currentState == InstanceState.Disabled;
 
     /// <summary>Returns true when a delete operation is allowed from the given state.</summary>
     /// <param name="currentState">The current instance state.</param>
+    /// <returns><see langword="true"/> if delete is permitted; otherwise <see langword="false"/>.</returns>
     public static bool CanDelete(InstanceState currentState) =>
         currentState is InstanceState.NotDeployed or InstanceState.Enabled or InstanceState.Disabled;
 
@@ -41,6 +45,7 @@ public static class StateTransitionValidator
     /// </summary>
     /// <param name="currentState">The current instance state.</param>
     /// <param name="operation">The operation name to validate (e.g. "deploy", "disable", "enable", "delete").</param>
+    /// <returns>An error message string if the transition is invalid; null if it is permitted.</returns>
     public static string? ValidateTransition(InstanceState currentState, string operation)
     {
         var allowed = operation.ToLowerInvariant() switch