Sheet Operations Overview

This section covers the data layer and maintenance features that keep an audit spreadsheet consistent:

Page	What it covers
Computed Columns	The derived-data engine (Computed.js), the sheet read layer (Sheets_data.js), and the Drive data layer (Google_drive_data.js)
Quality Check	The "Internal quality checks" sidebar and its five checks
Reset Functions	The "Reset sheets" repair operation and the batched diff-writer behind it
Spreadsheet Update	Schema migration between spreadsheet versions, including bulk updates across Drive
Preview	The rendered preview of the issue list (sidebar and large view)

A naming convention used throughout the project: a trailing underscore (someFunction_) marks a private function in Apps Script. It cannot be called from the sidebar HTML via google.script.run or bound to a menu item. Functions without a trailing underscore are menu handlers, sidebar endpoints, or shared cross-file helpers.