[jonaraphael]

Selecting numeric data cells now shows Sum, Average, and Count in the native VS Code status bar. Totals follow cell/range, row, column, and table selections; exclude headers, hidden rows, blanks, and text; and include matching rows beyond the rendered chunks. They update after committed edits and hide while editing, when no numeric cells are selected, or when another editor is active.

Retains the README rewrite, moves the detailed reference into docs/user-guide.md, and updates the documentation checks to follow that guide.

Validation

• npm ci --no-audit --no-fund with Node 20.
• npm test: compilation and all 716 tests pass, including CSV/TSV selection, filters, remote chunks, numeric edge cases, editing, stale messages, and editor lifecycle coverage.
• npm run lint: no errors; 82 existing warnings.
• Manual check in the VS Code Extension Development Host: select the Amount column containing 120.50, 99.50, and 80.00; the native status bar shows Sum: 300, Average: 100, Count: 3.

Screenshot