Refactor: Remove unused cellValueToSql import from LoggingDatabaseOperations

The `cellValueToSql` function was imported but never utilized within `src/loggingDatabaseOperations.ts`. Removing it cleans up the codebase and improves maintainability without impacting behavior.

Co-authored-by: zknpr <96851588+zknpr@users.noreply.github.com>

Author: google-labs-jules[bot]

src/loggingDatabaseOperations.ts

@@ -19,7 +19,7 @@ import type {
     ColumnMetadata,
     ColumnDefinition
 } from './core/types';
-import { escapeIdentifier, cellValueToSql } from './core/sql-utils';
+import { escapeIdentifier } from './core/sql-utils';
 import { buildSelectQuery, buildCountQuery } from './core/query-builder';
 
 export class LoggingDatabaseOperations implements DatabaseOperations {