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.NotificationService/NotificationOptions.cs

@@ -1,6 +1,15 @@
 namespace ScadaLink.NotificationService;
 
+/// <summary>
+/// Configuration options for the Notification Service.
+/// Most SMTP configuration is stored in the database (SmtpConfiguration entity).
+/// This provides fallback defaults and operational limits.
+/// </summary>
 public class NotificationOptions
 {
-    // Phase 0: minimal POCO — most SMTP configuration is stored in the database
+    /// <summary>Default connection timeout for SMTP connections.</summary>
+    public int ConnectionTimeoutSeconds { get; set; } = 30;
+
+    /// <summary>Maximum concurrent SMTP connections.</summary>
+    public int MaxConcurrentConnections { get; set; } = 5;
 }