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.

crates/wickra-core/src/lib.rs

@@ -56,9 +56,10 @@ pub use indicators::{
     DonchianStopOutput, DoubleBollinger, DoubleBollingerOutput, Dpo, EaseOfMovement,
     EhlersStochastic, ElderImpulse, Ema, EmpiricalModeDecomposition, Evwma, Fama, FibonacciPivots,
     FibonacciPivotsOutput, FisherTransform, ForceIndex, FractalChaosBands, FractalChaosBandsOutput,
-    Frama, GarmanKlassVolatility, HiLoActivator, HilbertDominantCycle, HistoricalVolatility, Hma,
-    HurstChannel, HurstChannelOutput, Inertia, InstantaneousTrendline, InverseFisherTransform, Jma,
-    Kama, Keltner, KeltnerOutput, Kst, KstOutput, Kvo, LaguerreRsi, LinRegAngle, LinRegChannel,
+    Frama, GarmanKlassVolatility, HeikinAshi, HeikinAshiOutput, HiLoActivator,
+    HilbertDominantCycle, HistoricalVolatility, Hma, HurstChannel, HurstChannelOutput, Ichimoku,
+    IchimokuOutput, Inertia, InstantaneousTrendline, InverseFisherTransform, Jma, Kama, Keltner,
+    KeltnerOutput, Kst, KstOutput, Kvo, LaguerreRsi, LinRegAngle, LinRegChannel,
     LinRegChannelOutput, LinRegSlope, LinearRegression, MaEnvelope, MaEnvelopeOutput,
     MacdIndicator, MacdOutput, Mama, MamaOutput, MarketFacilitationIndex, MassIndex,
     McGinleyDynamic, MedianPrice, Mfi, Mom, Natr, Nvi, Obv, ParkinsonVolatility, PercentB,