feat(scripts): add typed Parameters.Get<T>() helpers for script API

Replace raw dictionary casting with ScriptParameters wrapper that provides
Get<T>, Get<T?>, Get<T[]>, and Get<List<T>> with clear error messages,
numeric conversion, and JsonElement support for Inbound API parameters.

src/ScadaLink.InboundAPI/InboundScriptExecutor.cs

@@ -3,6 +3,7 @@ using Microsoft.CodeAnalysis.CSharp.Scripting;
 using Microsoft.CodeAnalysis.Scripting;
 using Microsoft.Extensions.Logging;
 using ScadaLink.Commons.Entities.InboundApi;
+using ScadaLink.Commons.Types;
 
 namespace ScadaLink.InboundAPI;
 
@@ -58,6 +59,7 @@ public class InboundScriptExecutor
                     typeof(Enumerable).Assembly,
                     typeof(Dictionary<,>).Assembly,
                     typeof(RouteHelper).Assembly,
+                    typeof(ScriptParameters).Assembly,
                     typeof(Microsoft.CSharp.RuntimeBinder.CSharpArgumentInfo).Assembly)
                 .WithImports(
                     "System",
@@ -152,7 +154,7 @@ public class InboundScriptExecutor
 /// </summary>
 public class InboundScriptContext
 {
-    public IReadOnlyDictionary<string, object?> Parameters { get; }
+    public ScriptParameters Parameters { get; }
     public RouteHelper Route { get; }
     public CancellationToken CancellationToken { get; }
 
@@ -161,7 +163,7 @@ public class InboundScriptContext
         RouteHelper route,
         CancellationToken cancellationToken = default)
     {
-        Parameters = parameters;
+        Parameters = new ScriptParameters(parameters);
         Route = route;
         CancellationToken = cancellationToken;
     }