feat: TA-Lib candlestick patterns — gap-three-methods/stalled/stick-sandwich/takuri (part 8 of 9) (#140)

Adds five TA-Lib candlestick patterns, each a streaming `Indicator<Input = Candle, Output = f64>` emitting the family's uniform `±1.0 / 0.0` sign convention, fully wired across the Rust core, Python / Node / WASM bindings, fuzz target and reference tests.

- **Upside Gap Three Methods** (`CDLXSIDEGAP3METHODS`) — a 3-bar bullish continuation: two white candles gap up, then a black candle opens within the second body and closes within the first; bullish +1.
- **Downside Gap Three Methods** (`CDLXSIDEGAP3METHODS`) — the bearish mirror: two black candles gap down, then a white candle opens within the second body and closes within the first; bearish -1.
- **Stalled Pattern** (`CDLSTALLEDPATTERN`) — a 3-bar bearish reversal warning: two long white candles then a small white candle riding the shoulder, signalling the rally is stalling; bearish -1.
- **Stick Sandwich** (`CDLSTICKSANDWICH`) — a 3-bar bullish reversal: two black candles closing at the same level sandwich a white candle, marking a support floor; bullish +1.
- **Takuri** (`CDLTAKURI`) — a single-bar bullish reversal, a strict Dragonfly Doji with a negligible upper shadow and very long lower shadow; bullish +1.

Body and shadow thresholds follow the geometric house style (fixed fractions of the bar range) rather than TA-Lib's rolling averages. Upside / Downside Gap Three Methods share the `CDLXSIDEGAP3METHODS` code, so the second carries a manual CHANGELOG entry (as with Rising / Falling Three Methods).

Counter 279 → 284 (mod-count == lib counted block; FAMILIES total 274 → 279).

Stacked on #139 (`feat/cdl-lines`); base retargets to `main` once the predecessor merges.

crates/wickra-core/src/lib.rs

@@ -65,19 +65,20 @@ pub use indicators::{
     ConditionalValueAtRisk, ConnorsRsi, Coppock, Counterattack, CumulativeVolumeDelta,
     CyberneticCycle, Decycler, DecyclerOscillator, Dema, DemandIndex, DemarkPivots,
     DemarkPivotsOutput, DepthSlope, DetrendedStdDev, Doji, DojiStar, Donchian, DonchianOutput,
-    DonchianStop, DonchianStopOutput, DoubleBollinger, DoubleBollingerOutput, Dpo, DragonflyDoji,
-    DrawdownDuration, EaseOfMovement, EffectiveSpread, EhlersStochastic, ElderImpulse, Ema,
-    EmpiricalModeDecomposition, Engulfing, EveningDojiStar, Evwma, FallingThreeMethods, Fama,
-    FibonacciPivots, FibonacciPivotsOutput, FisherTransform, Footprint, FootprintOutput,
-    ForceIndex, FractalChaosBands, FractalChaosBandsOutput, Frama, FundingBasis, FundingRate,
-    FundingRateMean, FundingRateZScore, GainLossRatio, GapSideBySideWhite, GarmanKlassVolatility,
-    GravestoneDoji, Hammer, HangingMan, Harami, HeikinAshi, HeikinAshiOutput, HiLoActivator,
-    HighWave, Hikkake, HikkakeModified, HilbertDominantCycle, HistoricalVolatility, Hma,
-    HomingPigeon, HurstChannel, HurstChannelOutput, HurstExponent, Ichimoku, IchimokuOutput,
-    IdenticalThreeCrows, InNeck, Inertia, InformationRatio, InitialBalance, InitialBalanceOutput,
-    InstantaneousTrendline, InverseFisherTransform, InvertedHammer, Jma, Kama, KellyCriterion,
-    Keltner, KeltnerOutput, Kicking, KickingByLength, Kst, KstOutput, Kurtosis, Kvo, KylesLambda,
-    LadderBottom, LaguerreRsi, LeadLagCrossCorrelation, LeadLagCrossCorrelationOutput, LinRegAngle,
+    DonchianStop, DonchianStopOutput, DoubleBollinger, DoubleBollingerOutput,
+    DownsideGapThreeMethods, Dpo, DragonflyDoji, DrawdownDuration, EaseOfMovement, EffectiveSpread,
+    EhlersStochastic, ElderImpulse, Ema, EmpiricalModeDecomposition, Engulfing, EveningDojiStar,
+    Evwma, FallingThreeMethods, Fama, FibonacciPivots, FibonacciPivotsOutput, FisherTransform,
+    Footprint, FootprintOutput, ForceIndex, FractalChaosBands, FractalChaosBandsOutput, Frama,
+    FundingBasis, FundingRate, FundingRateMean, FundingRateZScore, GainLossRatio,
+    GapSideBySideWhite, GarmanKlassVolatility, GravestoneDoji, Hammer, HangingMan, Harami,
+    HeikinAshi, HeikinAshiOutput, HiLoActivator, HighWave, Hikkake, HikkakeModified,
+    HilbertDominantCycle, HistoricalVolatility, Hma, HomingPigeon, HurstChannel,
+    HurstChannelOutput, HurstExponent, Ichimoku, IchimokuOutput, IdenticalThreeCrows, InNeck,
+    Inertia, InformationRatio, InitialBalance, InitialBalanceOutput, InstantaneousTrendline,
+    InverseFisherTransform, InvertedHammer, Jma, Kama, KellyCriterion, Keltner, KeltnerOutput,
+    Kicking, KickingByLength, Kst, KstOutput, Kurtosis, Kvo, KylesLambda, LadderBottom,
+    LaguerreRsi, LeadLagCrossCorrelation, LeadLagCrossCorrelationOutput, LinRegAngle,
     LinRegChannel, LinRegChannelOutput, LinRegSlope, LinearRegression, LiquidationFeatures,
     LiquidationFeaturesOutput, LongLeggedDoji, LongLine, LongShortRatio, MaEnvelope,
     MaEnvelopeOutput, MacdIndicator, MacdOutput, Mama, MamaOutput, MarketFacilitationIndex,
@@ -92,20 +93,21 @@ pub use indicators::{
     RisingThreeMethods, Roc, RogersSatchellVolatility, RollingVwap, RoofingFilter, Rsi, Rvi,
     RviVolatility, Rwi, RwiOutput, SeparatingLines, SharpeRatio, ShootingStar, ShortLine,
     SignedVolume, SineWave, Skewness, Sma, Smi, Smma, SortinoRatio, SpearmanCorrelation,
-    SpinningTop, StandardError, StandardErrorBands, StandardErrorBandsOutput, StarcBands,
-    StarcBandsOutput, Stc, StdDev, StepTrailingStop, StochRsi, Stochastic, StochasticOutput,
-    SuperSmoother, SuperTrend, SuperTrendOutput, TakerBuySellRatio, TdCombo, TdCountdown,
-    TdDeMarker, TdDifferential, TdLines, TdLinesOutput, TdOpen, TdPressure, TdRangeProjection,
-    TdRangeProjectionOutput, TdRei, TdRiskLevel, TdRiskLevelOutput, TdSequential,
-    TdSequentialOutput, TdSetup, Tema, TermStructureBasis, ThreeInside, ThreeLineStrike,
-    ThreeOutside, ThreeSoldiersOrCrows, ThreeStarsInSouth, Thrusting, Tii, TradeImbalance,
-    TreynorRatio, Trima, Trix, TrueRange, Tsi, Tsv, TtmSqueeze, TtmSqueezeOutput, Tweezer,
-    TwoCrows, TypicalPrice, UlcerIndex, UltimateOscillator, UpsideGapTwoCrows, ValueArea,
-    ValueAreaOutput, ValueAtRisk, Variance, VerticalHorizontalFilter, Vidya, VoltyStop,
-    VolumeOscillator, VolumePriceTrend, Vortex, VortexOutput, Vwap, VwapStdDevBands,
-    VwapStdDevBandsOutput, Vwma, Vzo, WaveTrend, WaveTrendOutput, WeightedClose, WilliamsFractals,
-    WilliamsFractalsOutput, WilliamsR, Wma, WoodiePivots, WoodiePivotsOutput, YangZhangVolatility,
-    YoyoExit, ZScore, ZeroLagMacd, ZeroLagMacdOutput, ZigZag, ZigZagOutput, Zlema, FAMILIES, T3,
+    SpinningTop, StalledPattern, StandardError, StandardErrorBands, StandardErrorBandsOutput,
+    StarcBands, StarcBandsOutput, Stc, StdDev, StepTrailingStop, StickSandwich, StochRsi,
+    Stochastic, StochasticOutput, SuperSmoother, SuperTrend, SuperTrendOutput, TakerBuySellRatio,
+    Takuri, TdCombo, TdCountdown, TdDeMarker, TdDifferential, TdLines, TdLinesOutput, TdOpen,
+    TdPressure, TdRangeProjection, TdRangeProjectionOutput, TdRei, TdRiskLevel, TdRiskLevelOutput,
+    TdSequential, TdSequentialOutput, TdSetup, Tema, TermStructureBasis, ThreeInside,
+    ThreeLineStrike, ThreeOutside, ThreeSoldiersOrCrows, ThreeStarsInSouth, Thrusting, Tii,
+    TradeImbalance, TreynorRatio, Trima, Trix, TrueRange, Tsi, Tsv, TtmSqueeze, TtmSqueezeOutput,
+    Tweezer, TwoCrows, TypicalPrice, UlcerIndex, UltimateOscillator, UpsideGapThreeMethods,
+    UpsideGapTwoCrows, ValueArea, ValueAreaOutput, ValueAtRisk, Variance, VerticalHorizontalFilter,
+    Vidya, VoltyStop, VolumeOscillator, VolumePriceTrend, Vortex, VortexOutput, Vwap,
+    VwapStdDevBands, VwapStdDevBandsOutput, Vwma, Vzo, WaveTrend, WaveTrendOutput, WeightedClose,
+    WilliamsFractals, WilliamsFractalsOutput, WilliamsR, Wma, WoodiePivots, WoodiePivotsOutput,
+    YangZhangVolatility, YoyoExit, ZScore, ZeroLagMacd, ZeroLagMacdOutput, ZigZag, ZigZagOutput,
+    Zlema, FAMILIES, T3,
 };
 // `FootprintLevel` is a row element of `FootprintOutput`, re-exported on its own
 // line so the indicator-count tooling (which scans the braced block above and