fix: escape backslashes in description strings (CodeQL alert)

Properly escape backslashes before escaping quotes to prevent
incomplete string escaping in generated .describe() calls.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: ochafik

scripts/generate-schemas.ts

@@ -1090,8 +1090,8 @@ function addTopLevelDescribe(sourceFile: SourceFile): void {
         // Skip if already has .describe() at the end
         if (/\.describe\([^)]+\)\s*$/.test(currentText)) continue;
 
-        // Escape quotes in description
-        const escapedDesc = descText.replace(/'/g, "\\'").replace(/\n/g, ' ');
+        // Escape backslashes first, then quotes and newlines
+        const escapedDesc = descText.replace(/\\/g, '\\\\').replace(/'/g, "\\'").replace(/\n/g, ' ');
 
         // Add .describe() to the schema
         decl.setInitializer(`${currentText}.describe('${escapedDesc}')`);