fix(sql): withhold the JSON parser's text on a malformed driver config (R06:S-8)

The factory quoted System.Text.Json's message (and attached the JsonException) into
the failure that reaches InitializeFailed -> health LastError -> /hosts; a pasted
connection-string literal is exactly the malformed text that lands there. The
message now names the instance and the line/byte position only, as the probe and
browser already do.

Refs #744
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Sql/SqlDriverFactoryExtensions.cs

@@ -194,8 +194,14 @@ public static class SqlDriverFactoryExtensions
         }
         catch (JsonException ex)
         {
+            // The parser's message AND the exception carrying it are withheld (R06:S-8), matching
+            // SqlDriverProbe and SqlDriverBrowser: System.Text.Json quotes the offending token, and a pasted
+            // connection-string literal is exactly the malformed text that lands here. This message becomes
+            // InitializeFailed -> health LastError -> /hosts. Line/byte position carry no content, so they stay.
             throw new InvalidOperationException(
-                $"Sql driver config for '{driverInstanceId}' is not valid JSON: {ex.Message}", ex);
+                $"Sql driver config for '{driverInstanceId}' is not valid JSON (line {ex.LineNumber + 1}, byte "
+                + $"{ex.BytePositionInLine}). The parser's message is withheld because the malformed text may "
+                + "carry a connection string.");
         }
     }