feat: 15 funciones finance — indicadores, riesgo e IO de mercado

11 funciones puras con implementación real:
SMA, EMA, RSI, BollingerBands, VWAP, LogReturn, AnnualizedVolatility,
SharpeRatio, MaxDrawdown, NormalizeOHLCV, TickToOHLCV

4 funciones impuras (stubs):
FetchOHLCV, StreamTicks, WriteOHLCVToParquet, LoadOHLCVFromDuckDB

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

functions/finance/normalize_ohlcv.md

@@ -0,0 +1,38 @@
+---
+name: normalize_ohlcv
+kind: function
+lang: go
+domain: finance
+version: "1.0.0"
+purity: pure
+signature: "func NormalizeOHLCV(open, high, low, close []float64, factor float64) ([]float64, []float64, []float64, []float64)"
+description: "Ajusta slices de precios OHLCV multiplicando cada valor por un factor dado."
+tags: [finance, ohlcv, normalize, adjust]
+uses_functions: []
+uses_types: [ohlcv_go_finance]
+returns: [ohlcv_go_finance]
+returns_optional: false
+error_type: ""
+imports: []
+tested: false
+tests: []
+test_file_path: ""
+file_path: "functions/finance/normalize_ohlcv.go"
+---
+
+# normalize_ohlcv
+
+Ajusta slices de precios OHLCV (open, high, low, close) multiplicando cada elemento por un factor escalar. Util para ajustes por splits, conversiones de divisa, o normalizacion de series.
+
+## Ejemplo
+
+```go
+o, h, l, c := finance.NormalizeOHLCV(
+    []float64{100, 200},
+    []float64{110, 210},
+    []float64{90, 190},
+    []float64{105, 205},
+    2.0,
+)
+// o = [200, 400], h = [220, 420], l = [180, 380], c = [210, 410]
+```