feat(family-13): add Ichimoku + Heikin-Ashi (#50)

Two new indicators in a brand-new "Ichimoku & alternative charts"
family:

- `Ichimoku` (Ichimoku Kinko Hyo): the full five-line cloud system
  (Tenkan-sen, Kijun-sen, Senkou Span A/B, Chikou Span). Classic
  (9, 26, 52, 26) defaults; configurable. Forward displacement is
  handled in an O(1) ring buffer so the visible Senkou A/B at bar n
  are the values computed at bar n-displacement.
- `HeikinAshi`: recursive candle smoothing transform emitting a
  four-field synthetic candle. Seeds ha_open from (open+close)/2 on
  the first bar.

Touchpoints: core + unit tests, mod.rs/lib.rs re-exports, Python +
Node + WASM bindings (multi-output via PyArray2 / interleaved Vec<f64>
/ Object+Float64Array), Python tests across smoke/new-indicators/
input-validation, Node parity tests, fuzz target (Candle), benches,
README family table + counter (71 -> 73, 8 -> 9 families), CHANGELOG.

Note: Renko, Kagi, and Point & Figure from the family-13 ideas list
are intentionally skipped. They are bar generators (the bar boundary
is defined by price moves, not by a fixed time interval) rather than
indicators that consume a candle stream, and belong in wickra-data
as candle/tick transforms alongside the existing tick-to-candle
aggregator and resampler.

fuzz/fuzz_targets/indicator_update_candle.rs

@@ -25,17 +25,18 @@ use libfuzzer_sys::fuzz_target;
 use wickra_core::{
     AccelerationBands, AcceleratorOscillator, AdOscillator, Adl, Adx, Adxr, Alligator,
     AnchoredVwap, Aroon, AroonOscillator, Atr, AtrBands, AtrTrailingStop, AwesomeOscillator,
-    AwesomeOscillatorHistogram, BalanceOfPower, BatchExt, Camarilla, Candle, Cci, ChaikinMoneyFlow,
-    ChaikinOscillator, ChaikinVolatility, ChandeKrollStop, ChandelierExit, ChoppinessIndex,
-    ClassicPivots, DemandIndex, DemarkPivots, Donchian, DonchianStop, EaseOfMovement, Evwma,
-    FibonacciPivots, ForceIndex, FractalChaosBands, GarmanKlassVolatility, HiLoActivator,
-    HurstChannel, Indicator, Inertia, Keltner, Kvo, MarketFacilitationIndex, MassIndex, MedianPrice,
-    Mfi, Natr, Nvi, Obv, ParkinsonVolatility, Pgo, Psar, Pvi, RogersSatchellVolatility, RollingVwap,
-    Rvi, Rwi, Smi, StarcBands, Stochastic, SuperTrend, TdCombo, TdCountdown, TdDeMarker,
-    TdDifferential, TdLines, TdOpen, TdPressure, TdRangeProjection, TdRei, TdRiskLevel,
-    TdSequential, TdSetup, TrueRange, Tsv, TtmSqueeze, TypicalPrice, UltimateOscillator, VoltyStop,
-    VolumeOscillator, VolumePriceTrend, Vortex, Vwap, VwapStdDevBands, Vwma, Vzo, WaveTrend,
-    WeightedClose, WilliamsFractals, WilliamsR, WoodiePivots, YangZhangVolatility, YoyoExit, ZigZag,
+    AwesomeOscillatorHistogram, BalanceOfPower, BatchExt, Camarilla, Candle, Cci,
+    ChaikinMoneyFlow, ChaikinOscillator, ChaikinVolatility, ChandeKrollStop, ChandelierExit,
+    ChoppinessIndex, ClassicPivots, DemandIndex, DemarkPivots, Donchian, DonchianStop,
+    EaseOfMovement, Evwma, FibonacciPivots, ForceIndex, FractalChaosBands,
+    GarmanKlassVolatility, HeikinAshi, HiLoActivator, HurstChannel, Ichimoku, Indicator,
+    Inertia, Keltner, Kvo, MarketFacilitationIndex, MassIndex, MedianPrice, Mfi, Natr, Nvi,
+    Obv, ParkinsonVolatility, Pgo, Psar, Pvi, RogersSatchellVolatility, RollingVwap, Rvi, Rwi,
+    Smi, StarcBands, Stochastic, SuperTrend, TdCombo, TdCountdown, TdDeMarker, TdDifferential,
+    TdLines, TdOpen, TdPressure, TdRangeProjection, TdRei, TdRiskLevel, TdSequential, TdSetup,
+    TrueRange, Tsv, TtmSqueeze, TypicalPrice, UltimateOscillator, VoltyStop, VolumeOscillator,
+    VolumePriceTrend, Vortex, Vwap, VwapStdDevBands, Vwma, Vzo, WaveTrend, WeightedClose,
+    WilliamsFractals, WilliamsR, WoodiePivots, YangZhangVolatility, YoyoExit, ZigZag,
 };
 
 /// Convert a flat `f64` stream into a `Vec<Candle>` by chunking it into
@@ -165,6 +166,24 @@ fuzz_target!(|data: Vec<f64>| {
         let _ = Stochastic::new(14, 3).unwrap().batch(&candles);
     }
 
+    // --- Ichimoku (5 lines, hand-rolled because of multi-Option output) ---
+    {
+        let mut ichi = Ichimoku::classic();
+        for c in &candles {
+            let _ = ichi.update(*c);
+        }
+        let _ = Ichimoku::classic().batch(&candles);
+    }
+
+    // --- Heikin-Ashi (4-field candle transform) ---
+    {
+        let mut ha = HeikinAshi::new();
+        for c in &candles {
+            let _ = ha.update(*c);
+        }
+        let _ = HeikinAshi::new().batch(&candles);
+    }
+
     // --- DeMark family ---
     drive(|| TdSetup::new(4, 9).unwrap(), &candles);
     drive(|| TdDeMarker::new(14).unwrap(), &candles);