refactor: restructure to clean architecture

fix: restore ScoringConfig improvements lost in refactor commit

docs: rewrite README and CLAUDE.md to reflect current architecture

code-format

code fixes

tests/DataMapper.test.js

@@ -0,0 +1,92 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { mapToStandardFormat } from '../src/screener/DataMapper.js';
+
+const base = {
+  price: { quoteType: 'EQUITY', regularMarketPrice: 150 },
+  assetProfile: { sector: 'Technology', industry: 'Software', category: '' },
+  financialData: {
+    quickRatio: 1.2,
+    debtToEquity: 150,
+    freeCashflow: 5e9,
+    revenueGrowth: 0.15,
+    profitMargins: 0.25,
+    operatingMargins: 0.3,
+    returnOnEquity: 0.2,
+    earningsGrowth: 0.12,
+    operatingCashflow: 8e9,
+  },
+  defaultKeyStatistics: { pegRatio: null, forwardPE: 28, sharesOutstanding: 1e9, priceToBook: 12 },
+  summaryDetail: {
+    trailingAnnualDividendYield: 0.005,
+    trailingPE: 30,
+    beta: 1.2,
+    fiftyTwoWeekHigh: 200,
+    fiftyTwoWeekLow: 120,
+  },
+};
+
+test('maps EQUITY quote type to STOCK', () => {
+  const result = mapToStandardFormat('AAPL', base);
+  assert.equal(result.type, 'STOCK');
+  assert.equal(result.ticker, 'AAPL');
+});
+
+test('computes PEG from trailingPE / earningsGrowth when Yahoo returns null', () => {
+  const result = mapToStandardFormat('AAPL', base);
+  const expected = +(30 / (0.12 * 100)).toFixed(2); // trailingPE=30, earningsGrowth=12%
+  assert.equal(result.pegRatio, expected);
+});
+
+test('uses Yahoo pegRatio when available', () => {
+  const summary = {
+    ...base,
+    defaultKeyStatistics: { ...base.defaultKeyStatistics, pegRatio: 1.5 },
+  };
+  const result = mapToStandardFormat('AAPL', summary);
+  assert.equal(result.pegRatio, 1.5);
+});
+
+test('debtToEquity is divided by 100', () => {
+  const result = mapToStandardFormat('AAPL', base);
+  assert.equal(result.debtToEquity, 1.5); // 150 / 100
+});
+
+test('maps ETF quoteType to ETF', () => {
+  const etfSummary = {
+    ...base,
+    price: { ...base.price, quoteType: 'ETF' },
+    assetProfile: { category: 'Large Blend' },
+  };
+  const result = mapToStandardFormat('VOO', etfSummary);
+  assert.equal(result.type, 'ETF');
+});
+
+test('classifies bond ETF from category keyword', () => {
+  const bondSummary = {
+    ...base,
+    price: { ...base.price, quoteType: 'ETF' },
+    assetProfile: { category: 'Intermediate-Term Bond' },
+  };
+  const result = mapToStandardFormat('BND', bondSummary);
+  assert.equal(result.type, 'BOND');
+});
+
+test('FCF yield is computed when data available', () => {
+  const result = mapToStandardFormat('AAPL', base);
+  assert.notEqual(result.fcfYield, null);
+  assert(result.fcfYield > 0);
+});
+
+test('metrics are null (not 0) when data missing', () => {
+  const sparse = {
+    price: { quoteType: 'EQUITY', regularMarketPrice: 100 },
+    financialData: {},
+    defaultKeyStatistics: {},
+    summaryDetail: {},
+    assetProfile: {},
+  };
+  const result = mapToStandardFormat('X', sparse);
+  assert.equal(result.pegRatio, null);
+  assert.equal(result.quickRatio, null);
+});