Full HyperFormula engine wired into the grid as a peer-optional dep. Editable spreadsheet with A1-style cell refs, dozens of formulas across math (SUM / SUMIF), lookup (VLOOKUP / INDEX-MATCH), text (CONCAT / UPPER), date (TODAY / DATEDIF), logical (IF nests), financial (PMT / IRR / NPV), statistical (AVERAGE / MAX / RANK).