fix(data-connection): resolve DataConnectionLayer-006..012 — quality-counter reconciliation, per-tag batch reads, configurable failover threshold, dedup retry, stale-callback guard, secure cert default

src/ScadaLink.DataConnectionLayer/DataConnectionOptions.cs

@@ -13,4 +13,11 @@ public class DataConnectionOptions
 
     /// <summary>Timeout for synchronous write operations to devices.</summary>
     public TimeSpan WriteTimeout { get; set; } = TimeSpan.FromSeconds(30);
+
+    /// <summary>
+    /// Minimum time a connection must stay up before it is considered stable.
+    /// If a connection drops before this threshold, it counts as an unstable
+    /// disconnect toward the failover retry count (DataConnectionLayer-009).
+    /// </summary>
+    public TimeSpan StableConnectionThreshold { get; set; } = TimeSpan.FromSeconds(60);
 }