Phase 8: Production readiness — failover tests, security hardening, sandboxing, deployment docs

- WP-1-3: Central/site failover + dual-node recovery tests (17 tests)
- WP-4: Performance testing framework for target scale (7 tests)
- WP-5: Security hardening (LDAPS, JWT key length, no secrets in logs) (11 tests)
- WP-6: Script sandboxing adversarial tests (28 tests, all forbidden APIs)
- WP-7: Recovery drill test scaffolds (5 tests)
- WP-8: Observability validation (structured logs, correlation IDs, metrics) (6 tests)
- WP-9: Message contract compatibility (forward/backward compat) (18 tests)
- WP-10: Deployment packaging (installation guide, production checklist, topology)
- WP-11: Operational runbooks (failover, troubleshooting, maintenance)
92 new tests, all passing. Zero warnings.

src/ScadaLink.InboundAPI/InboundScriptExecutor.cs

@@ -0,0 +1,109 @@
+using System.Text.Json;
+using Microsoft.Extensions.Logging;
+using ScadaLink.Commons.Entities.InboundApi;
+
+namespace ScadaLink.InboundAPI;
+
+/// <summary>
+/// WP-3: Executes the C# script associated with an inbound API method.
+/// The script receives input parameters and a route helper, and returns a result
+/// that is serialized as the JSON response.
+///
+/// In a full implementation this would use Roslyn scripting. For now, scripts
+/// are a simple dispatch table so the rest of the pipeline can be tested end-to-end.
+/// </summary>
+public class InboundScriptExecutor
+{
+    private readonly ILogger<InboundScriptExecutor> _logger;
+    private readonly Dictionary<string, Func<InboundScriptContext, Task<object?>>> _scriptHandlers = new();
+
+    public InboundScriptExecutor(ILogger<InboundScriptExecutor> logger)
+    {
+        _logger = logger;
+    }
+
+    /// <summary>
+    /// Registers a compiled script handler for a method name.
+    /// In production, this would be called after Roslyn compilation of the method's Script property.
+    /// </summary>
+    public void RegisterHandler(string methodName, Func<InboundScriptContext, Task<object?>> handler)
+    {
+        _scriptHandlers[methodName] = handler;
+    }
+
+    /// <summary>
+    /// Executes the script for the given method with the provided context.
+    /// </summary>
+    public async Task<InboundScriptResult> ExecuteAsync(
+        ApiMethod method,
+        IReadOnlyDictionary<string, object?> parameters,
+        RouteHelper route,
+        TimeSpan timeout,
+        CancellationToken cancellationToken = default)
+    {
+        try
+        {
+            using var cts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
+            cts.CancelAfter(timeout);
+
+            var context = new InboundScriptContext(parameters, route, cts.Token);
+
+            object? result;
+            if (_scriptHandlers.TryGetValue(method.Name, out var handler))
+            {
+                result = await handler(context).WaitAsync(cts.Token);
+            }
+            else
+            {
+                // No compiled handler — this means the script hasn't been registered.
+                // In production, we'd compile the method.Script and cache it.
+                return new InboundScriptResult(false, null, "Script not compiled or registered for this method");
+            }
+
+            var resultJson = result != null
+                ? JsonSerializer.Serialize(result)
+                : null;
+
+            return new InboundScriptResult(true, resultJson, null);
+        }
+        catch (OperationCanceledException)
+        {
+            _logger.LogWarning("Script execution timed out for method {Method}", method.Name);
+            return new InboundScriptResult(false, null, "Script execution timed out");
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "Script execution failed for method {Method}", method.Name);
+            // WP-5: Safe error message, no internal details
+            return new InboundScriptResult(false, null, "Internal script error");
+        }
+    }
+}
+
+/// <summary>
+/// Context provided to inbound API scripts.
+/// </summary>
+public class InboundScriptContext
+{
+    public IReadOnlyDictionary<string, object?> Parameters { get; }
+    public RouteHelper Route { get; }
+    public CancellationToken CancellationToken { get; }
+
+    public InboundScriptContext(
+        IReadOnlyDictionary<string, object?> parameters,
+        RouteHelper route,
+        CancellationToken cancellationToken = default)
+    {
+        Parameters = parameters;
+        Route = route;
+        CancellationToken = cancellationToken;
+    }
+}
+
+/// <summary>
+/// Result of executing an inbound API script.
+/// </summary>
+public record InboundScriptResult(
+    bool Success,
+    string? ResultJson,
+    string? ErrorMessage);