Modernize harmony.py / retire the per-country food_prices_quantities_and_expenditures.py family

[ligon]

Background

lsms_library/harmony.py is a CLI cross-country consistency check that predates the Country API. It directly reads the legacy var/food_expenditures.parquet, var/food_prices.parquet, and var/household_characteristics.parquet for a given country, then uses local_tools.add_markets_from_other_features (whose only call site is harmony.py itself) to attach a market index via the obsolete other_features infrastructure (per CLAUDE.md).

Verified zero callers anywhere in the repo: notebooks, tests, scripts, docs, makefiles all clean. The helper it imports (add_markets_from_other_features) is similarly orphan.

Cascade

The legacy parquets harmony reads are produced by per-country food_prices_quantities_and_expenditures.py scripts. They currently exist in 12 countries: Afghanistan, Burkina_Faso, Cambodia, CotedIvoire, Ethiopia, GhanaLSS, GhanaSPS, Guatemala, Malawi, Panama, Senegal, Tanzania.

For 11 of these, the framework's _FOOD_DERIVED path in country.py:2541-2571 shadows the legacy outputs — Country(X).food_expenditures() / .food_prices() / .food_quantities() derive from food_acquired via transformations.food_*_from_acquired rather than reading the legacy parquets. The legacy script's outputs are written but never read by the Country API.

Uganda is the exception: derivation fails because food_acquired lacks a single Expenditure column (split into value_home/away/own/inkind). Per CLAUDE.md, blocked on #169 (canonical food_acquired columns).

Proposed direction

1. Modern equivalent of harmony's checks, Country-API-based. Sketch:
   • Country(X).consistency_check() (or top-level lsms_library.harmony.audit(country)) calls Country(X).food_expenditures(), .food_prices(), .household_characteristics(), runs the same index-orientation / market-attachment / label-overlap assertions, raises clearly on failure.
   • All inputs go through _finalize_result (kinship expansion, canonical spelling, id_walk), so the audit operates on the canonical API form rather than the raw legacy parquet form.
2. Once the modern equivalent exists, retire the per-country food_prices_quantities_and_expenditures.py (12 files, ~290 lines), the corresponding Makefile rules, the orphan local_tools.add_markets_from_other_features helper, and lsms_library/harmony.py itself. Leave Uganda alone until Design: food_acquired canonical columns (+ cascade to food_prices, food_quantities) #169 lands.

First step

A linked PR does Phase 1 for Malawi only — removes Malawi's instance of the legacy script (whose outputs are already shadowed), trims dead helpers in Malawi/_/malawi.py, and updates the Makefile / CONTENTS.org accordingly. Treats Malawi as the proof-of-concept for the cross-country pattern.

Related

• Malawi: Incomplete conversion_to_kgs and missing Food Conversion Table #116 — Malawi-specific incomplete conversion table (orthogonal)
• Design: food_acquired canonical columns (+ cascade to food_prices, food_quantities) #169 — canonical food_acquired columns (blocks Uganda's retirement)
• `CLAUDE.md` ## Cache Behavior (v0.7.0+) — framework derivation path
• `transformations.py:_FOOD_DERIVED`, `country.py:2541-2571` — current dispatch