fpa-excel-modellisted

# Live-formula Excel model (operate) ## Overview Finance professionals ultimately want a workbook where changing an assumption recalculates the model. This skill produces one from the model structure, with named assumption cells and real formulas, then proves it reproduces the engine before it ships. Static value dumps stay with `forecast_to_excel`; this skill is for living models. **Core principle:** no workbook ships unverified. The workbook is generated from the model, never hand-edited values. ## The standard model For the kernel's monthly model, one call: ```python import pyfpa cfg = pyfpa.load_config("config.yaml") pyfpa.model_to_excel(cfg, "model.xlsx") ``` Or via CLI: `python3 -m pyfpa.cli model-export <company-root> --config config.yaml --out model.xlsx`. The workbook has an Assumptions sheet (every driver a named, editable cell: growth, COGS pct, seasonality, DSO/DIO/DPO, debt, tax, D&A, capex) and a Model sheet where every line of the monthly P&L and cash flow is a formula referencing those names. ## Any other cadence or layout Quarterly, weekly, a tab per segment, a lender view: these are YOUR work, not kernel variants. Compose `pyfpa.excel.toolkit` (`add_named_cell`, `add_named_row`, `fill_formula_row`, formats) in a company-specific exporter under the generated namespace (`models/generated/<name>/`), then register it: ```bash python3 -m pyfpa.cli entrypoint-register <root> --name excel-quarterly --kind report \ --description "Quarterly live-formula