docs(sql-dialect): record the browse consequence of Oracle's ALL_USERS schema list (Driver.Sql.Dialect-003)

ListSchemasSql has two consumers and the remarks only justified the divergence
from the catalog gate's viewpoint. SqlBrowseSession.RootAsync renders every row
as an expandable schema, so an Oracle browse offers every database user. The
narrower ALL_TABLES/ALL_VIEWS query is named, along with why it is not taken
here: it narrows the gate too, and that is a poll-path behaviour change only a
real Oracle server can gate.

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

@@ -141,10 +141,26 @@ public sealed class OracleDialect : ISqlDialect
     ///     user), aliased to the <c>TABLE_SCHEMA</c> column name the catalog readers project by.
     /// </summary>
     /// <remarks>
-    ///     Broader than the SQL Server dialect's <c>DISTINCT TABLE_SCHEMA FROM INFORMATION_SCHEMA.TABLES</c>,
+    ///     <para>Broader than the SQL Server dialect's <c>DISTINCT TABLE_SCHEMA FROM
-    ///     which lists only schemas that own an object: <c>ALL_USERS</c> includes empty ones. Harmless here —
+    ///     INFORMATION_SCHEMA.TABLES</c>, which lists only schemas that own an object: <c>ALL_USERS</c>
-    ///     the list is used to resolve an authored schema name to the catalog's own spelling, and a schema
+    ///     includes empty ones. Harmless for the <b>catalog gate</b> — the list is used to resolve an authored
-    ///     holding no tables simply resolves and then matches no relation.
+    ///     schema name to the catalog's own spelling, and a schema holding no tables simply resolves and then
+    ///     matches no relation.</para>
+    ///     <para>⚠️ <b>It is NOT harmless for the browse tree, and that is a known, accepted trade rather than
+    ///     an oversight (Driver.Sql.Dialect-003).</b> This query has two consumers, and only the gate wants the
+    ///     broad list: <c>SqlBrowseSession.RootAsync</c> renders every row as an expandable schema folder, so
+    ///     on a real Oracle estate the operator is offered every database <em>user</em> — hundreds of them,
+    ///     nearly all empty, with nothing in the tree distinguishing the ones that hold a relation until each
+    ///     is expanded.</para>
+    ///     <para><b>The narrower query is
+    ///     <c>SELECT DISTINCT owner FROM ALL_TABLES UNION SELECT DISTINCT owner FROM ALL_VIEWS</c></b>, which
+    ///     would match what the other two dialects list and what the browse tree wants. It is deliberately not
+    ///     taken here because it also <em>narrows the gate</em>: a tag naming an empty schema today resolves and
+    ///     then fails at the table level, and afterwards would fail at the schema level with a different
+    ///     message — a behaviour change on the poll path that can only be validated against a real Oracle
+    ///     server (<c>OracleReadTests</c>), never offline, for the same reason the <c>p_</c> bind-prefix defect
+    ///     was invisible until it ran. Make the swap when an Oracle estate is available to gate it on, and
+    ///     change both consumers' expectations in the same commit.</para>
     /// </remarks>
     public string ListSchemasSql =>
         "SELECT username AS TABLE_SCHEMA FROM ALL_USERS ORDER BY username";