fix(audit): robust central options binding + interval clamps + doc/contract fixes (review)

src/ZB.MOM.WW.ScadaBridge.AuditLog/Central/SiteAuditReconciliationOptions.cs

@@ -31,18 +31,45 @@ public sealed class SiteAuditReconciliationOptions
     /// <summary>
     /// Test-only override for finer control over the tick cadence than
     /// whole-second resolution allows. When non-null, takes precedence over
-    /// <see cref="ReconciliationIntervalSeconds"/>. Not bound from config —
-    /// production config exposes <see cref="ReconciliationIntervalSeconds"/>
-    /// only.
+    /// <see cref="ReconciliationIntervalSeconds"/> AND bypasses the
+    /// <see cref="ReconciliationInterval"/> minimum clamp (so tests can use
+    /// millisecond cadences). Production config exposes
+    /// <see cref="ReconciliationIntervalSeconds"/> only and never sets this
+    /// knob — but because the options class is <c>Bind</c>-ed wholesale, a
+    /// config value at <c>AuditLog:Reconciliation:ReconciliationIntervalOverride</c>
+    /// WOULD bind if present; operators must not set it.
     /// </summary>
     public TimeSpan? ReconciliationIntervalOverride { get; set; }
 
     /// <summary>
-    /// Resolves the effective tick interval, honouring the test override when
-    /// set. Falls back to <see cref="ReconciliationIntervalSeconds"/>.
+    /// Minimum interval the config-bound <see cref="ReconciliationIntervalSeconds"/>
+    /// can resolve to. Clamps a misconfigured <c>ReconciliationIntervalSeconds: 0</c>
+    /// (or a negative value) away from <see cref="TimeSpan.Zero"/>, which would make
+    /// Akka's <c>ScheduleTellRepeatedlyCancelable</c> spin. The test-only
+    /// <see cref="ReconciliationIntervalOverride"/> bypasses this clamp so unit tests
+    /// can still drop the cadence to milliseconds.
     /// </summary>
-    public TimeSpan ReconciliationInterval =>
-        ReconciliationIntervalOverride ?? TimeSpan.FromSeconds(ReconciliationIntervalSeconds);
+    private static readonly TimeSpan MinConfiguredInterval = TimeSpan.FromSeconds(1);
+
+    /// <summary>
+    /// Resolves the effective tick interval, honouring the test override when
+    /// set. Falls back to <see cref="ReconciliationIntervalSeconds"/>, clamped to at
+    /// least <see cref="MinConfiguredInterval"/> so a zero/negative config value can
+    /// never yield <see cref="TimeSpan.Zero"/> (which would spin the scheduler).
+    /// </summary>
+    public TimeSpan ReconciliationInterval
+    {
+        get
+        {
+            if (ReconciliationIntervalOverride is { } overrideValue)
+            {
+                return overrideValue;
+            }
+
+            var resolved = TimeSpan.FromSeconds(ReconciliationIntervalSeconds);
+            return resolved < MinConfiguredInterval ? MinConfiguredInterval : resolved;
+        }
+    }
 
     /// <summary>
     /// Maximum number of <see cref="ZB.MOM.WW.ScadaBridge.Commons.Entities.Audit.AuditEvent"/>