fix(sql): chunk the key-value IN list at the dialect's bind ceiling (Driver.Sql-002, Driver.Sql.Dialect-002)

ISqlDialect gains MaxBindParameters — the per-command ceiling the seam was
missing while modelling everything else that differs per backend: 2098 usable
of SQL Server's 2100 (sp_executesql spends two), 1000 for Oracle's IN-list
limit (ORA-01795, tighter than its 64k bind count), 65535 for the Postgres
Bind message.

SqlGroupPlanner.AddKeyValuePlans now emits several plans for one group when
its distinct keys exceed that ceiling, instead of one statement the provider
refuses after the connection opened — which left every tag in an EAV group
publishing BadCommunicationError on every poll, permanently, and reported the
database endpoint as down. Chunks share the group key; members follow their
own key so a shared keyValue never splits. SqlPollReader is unchanged: it runs
one command per plan and slices each plan's own Members back, proven by a
fixture read at a ceiling of 1.

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Sql.Dialect/PostgresDialect.cs

@@ -64,6 +64,14 @@ public sealed class PostgresDialect : ISqlDialect
         // Intentionally empty: see the summary.
     }
 
+    /// <summary>
+    ///     65535 — the extended-query protocol carries the parameter count as a signed/unsigned 16-bit field
+    ///     in <c>Bind</c>, so that is a protocol ceiling rather than a server setting, and Npgsql raises it
+    ///     client-side before a round-trip. Far above anything a poll group reaches in practice; it is here so
+    ///     the planner never has to special-case "this dialect has no meaningful limit".
+    /// </summary>
+    public int MaxBindParameters => 65535;
+
     /// <inheritdoc/>
     public string LivenessSql => "SELECT 1";