Add 10 pairwise stat-arb indicators to Price Statistics (#154)

Adds ten pairwise `(f64, f64)` indicators to the **Price Statistics** family, completing the A1 stat-arb expansion block.

## Indicators

**Scalar output:**
- **RollingCorrelation** — rolling Pearson correlation of period-over-period *returns* (distinct from level-based `PearsonCorrelation`).
- **RollingCovariance** — rolling covariance of returns.
- **OuHalfLife** — Ornstein–Uhlenbeck half-life of mean reversion of the spread `a − b`.
- **SpreadHurst** — Hurst exponent of the spread (variance-of-lagged-differences fit) for regime detection.
- **DistanceSsd** — Gatev sum-of-squared-deviations between two start-normalised series.
- **BetaNeutralSpread** — rolling OLS regression residual `a − (α + β·b)`.
- **VarianceRatio** — Lo–MacKinlay variance-ratio test on the spread (two params: `period`, `q`).
- **GrangerCausality** — F-statistic for whether `b` predicts `a` (two params: `period`, `lag`).

**Struct output (custom bindings):**
- **KalmanHedgeRatio** — dynamic hedge ratio via a Kalman filter → `{ hedgeRatio, intercept, spread }`.
- **SpreadBollingerBands** — Bollinger bands on the spread → `{ middle, upper, lower, percentB }`.

## Notes
- No new traits or input families: all use the native `Indicator<Input = (f64, f64)>` (precedent `Beta`, `Cointegration`).
- Adds `Error::InvalidParameter` for floating-point constructor parameters (Kalman `delta`/`observation_var`, `num_std`).
- Full Python/Node/WASM bindings; the two struct-output indicators are hand-written, the rest use the pair macros.
- Indicator count 315 → 325; README, family rows, `__init__`, fuzz target, and CHANGELOG updated.

## Verification
- `cargo test --workspace --all-features` — green (2676 core lib + 308 doc).
- `cargo clippy --workspace --all-targets --all-features -- -D warnings` — clean.
- Node: `npm run build && npm test` — 410 passing (`index.d.ts`/`index.js` regenerated).
- Python: `pytest` — 684 passing.

bindings/node/index.js

@@ -310,7 +310,7 @@ if (!nativeBinding) {
   throw new Error(`Failed to load native binding`)
 }
 
-const { version, SMA, EMA, WMA, RSI, DEMA, TEMA, HMA, ROC, TRIX, SMMA, TRIMA, ZLEMA, MOM, CMO, DPO, StdDev, UlcerIndex, VerticalHorizontalFilter, ZScore, McGinleyDynamic, FRAMA, SuperSmoother, FisherTransform, Decycler, CenterOfGravity, CyberneticCycle, InstantaneousTrendline, EhlersStochastic, RVIVolatility, Variance, CoefficientOfVariation, Skewness, Kurtosis, StandardError, DetrendedStdDev, RSquared, MedianAbsoluteDeviation, MIDPOINT, ROCP, ROCR, ROCR100, LINEARREG_INTERCEPT, TSF, Autocorrelation, HurstExponent, PearsonCorrelation, Beta, PairwiseBeta, SpearmanCorrelation, PairSpreadZScore, LeadLagCrossCorrelation, Cointegration, RelativeStrengthAB, MACD, MACDFIX, MACDEXT, BollingerBands, ATR, PLUS_DM, MINUS_DM, PLUS_DI, MINUS_DI, DX, MIDPRICE, AVGPRICE, SAREXT, HT_PHASOR, Stochastic, OBV, ADX, ADXR, CCI, WilliamsR, MFI, PSAR, Keltner, Donchian, VWAP, RollingVWAP, AwesomeOscillator, Aroon, Inertia, ConnorsRSI, LaguerreRSI, SMI, KST, PGO, RVI, AwesomeOscillatorHistogram, STC, ElderImpulse, ZeroLagMACD, CFO, APO, KAMA, EVWMA, Alligator, JMA, VIDYA, ALMA, T3, TSI, PMO, TII, ADL, VolumePriceTrend, ChaikinMoneyFlow, ChaikinOscillator, ForceIndex, NVI, PVI, VolumeOscillator, KVO, WilliamsAD, AnchoredRSI, AnchoredVWAP, DemandIndex, TSV, VZO, MarketFacilitationIndex, EaseOfMovement, SuperTrend, ChandelierExit, ChandeKrollStop, AtrTrailingStop, HiLoActivator, VoltyStop, YoyoExit, DonchianStop, PercentageTrailingStop, StepTrailingStop, RenkoTrailingStop, TypicalPrice, MedianPrice, WeightedClose, LinearRegression, LinRegSlope, AcceleratorOscillator, BalanceOfPower, ChoppinessIndex, TrueRange, ChaikinVolatility, YangZhangVolatility, RogersSatchellVolatility, GarmanKlassVolatility, ParkinsonVolatility, LinRegAngle, BollingerBandwidth, PercentB, NATR, HistoricalVolatility, AroonOscillator, WaveTrend, RWI, Vortex, MassIndex, StochRSI, UltimateOscillator, PPO, Coppock, VWMA, MaEnvelope, AccelerationBands, StarcBands, AtrBands, HurstChannel, LinRegChannel, StandardErrorBands, DoubleBollinger, TtmSqueeze, FractalChaosBands, VwapStdDevBands, ClassicPivots, FibonacciPivots, Camarilla, WoodiePivots, DemarkPivots, WilliamsFractals, ZigZag, TDSetup, TDSequential, TDDeMarker, TDREI, TDPressure, TDCombo, TDCountdown, TDLines, TDRangeProjection, TDDifferential, TDOpen, TDRiskLevel, InverseFisherTransform, DecyclerOscillator, RoofingFilter, EmpiricalModeDecomposition, HT_DCPHASE, HT_TRENDMODE, HilbertDominantCycle, AdaptiveCycle, SineWave, MAMA, FAMA, Ichimoku, HeikinAshi, ValueArea, VolumeProfile, TpoProfile, InitialBalance, OpeningRange, Doji, Hammer, InvertedHammer, HangingMan, ShootingStar, Engulfing, Harami, MorningEveningStar, ThreeSoldiersOrCrows, PiercingDarkCloud, Marubozu, Tweezer, SpinningTop, ThreeInside, ThreeOutside, TwoCrows, UpsideGapTwoCrows, IdenticalThreeCrows, ThreeLineStrike, ThreeStarsInSouth, AbandonedBaby, AdvanceBlock, BeltHold, Breakaway, Counterattack, DojiStar, DragonflyDoji, GravestoneDoji, LongLeggedDoji, RickshawMan, EveningDojiStar, MorningDojiStar, GapSideBySideWhite, HighWave, Hikkake, HikkakeModified, HomingPigeon, OnNeck, InNeck, Thrusting, SeparatingLines, Kicking, KickingByLength, LadderBottom, MatHold, MatchingLow, LongLine, ShortLine, RisingThreeMethods, FallingThreeMethods, UpsideGapThreeMethods, DownsideGapThreeMethods, StalledPattern, StickSandwich, Takuri, ClosingMarubozu, OpeningMarubozu, TasukiGap, UniqueThreeRiver, ConcealingBabySwallow, OrderBookImbalanceTop1, OrderBookImbalanceFull, Microprice, QuotedSpread, DepthSlope, OrderBookImbalanceTopN, SignedVolume, CumulativeVolumeDelta, TradeImbalance, EffectiveSpread, RealizedSpread, KylesLambda, Footprint, FundingRate, FundingRateMean, FundingRateZScore, FundingBasis, OpenInterestDelta, OIPriceDivergence, OIWeighted, LongShortRatio, TakerBuySellRatio, LiquidationFeatures, TermStructureBasis, CalendarSpread, AdvanceDecline, SharpeRatio, SortinoRatio, CalmarRatio, OmegaRatio, MaxDrawdown, AverageDrawdown, DrawdownDuration, PainIndex, ValueAtRisk, ConditionalValueAtRisk, ProfitFactor, GainLossRatio, RecoveryFactor, KellyCriterion, TreynorRatio, InformationRatio, RenkoBars, KagiBars, PointAndFigureBars, Alpha } = nativeBinding
+const { version, SMA, EMA, WMA, RSI, DEMA, TEMA, HMA, ROC, TRIX, SMMA, TRIMA, ZLEMA, MOM, CMO, DPO, StdDev, UlcerIndex, VerticalHorizontalFilter, ZScore, McGinleyDynamic, FRAMA, SuperSmoother, FisherTransform, Decycler, CenterOfGravity, CyberneticCycle, InstantaneousTrendline, EhlersStochastic, RVIVolatility, Variance, CoefficientOfVariation, Skewness, Kurtosis, StandardError, DetrendedStdDev, RSquared, MedianAbsoluteDeviation, MIDPOINT, ROCP, ROCR, ROCR100, LINEARREG_INTERCEPT, TSF, Autocorrelation, HurstExponent, PearsonCorrelation, Beta, PairwiseBeta, SpearmanCorrelation, RollingCorrelation, RollingCovariance, OuHalfLife, SpreadHurst, DistanceSsd, BetaNeutralSpread, PairSpreadZScore, LeadLagCrossCorrelation, Cointegration, RelativeStrengthAB, VarianceRatio, GrangerCausality, KalmanHedgeRatio, SpreadBollingerBands, MACD, MACDFIX, MACDEXT, BollingerBands, ATR, PLUS_DM, MINUS_DM, PLUS_DI, MINUS_DI, DX, MIDPRICE, AVGPRICE, SAREXT, HT_PHASOR, Stochastic, OBV, ADX, ADXR, CCI, WilliamsR, MFI, PSAR, Keltner, Donchian, VWAP, RollingVWAP, AwesomeOscillator, Aroon, Inertia, ConnorsRSI, LaguerreRSI, SMI, KST, PGO, RVI, AwesomeOscillatorHistogram, STC, ElderImpulse, ZeroLagMACD, CFO, APO, KAMA, EVWMA, Alligator, JMA, VIDYA, ALMA, T3, TSI, PMO, TII, ADL, VolumePriceTrend, ChaikinMoneyFlow, ChaikinOscillator, ForceIndex, NVI, PVI, VolumeOscillator, KVO, WilliamsAD, AnchoredRSI, AnchoredVWAP, DemandIndex, TSV, VZO, MarketFacilitationIndex, EaseOfMovement, SuperTrend, ChandelierExit, ChandeKrollStop, AtrTrailingStop, HiLoActivator, VoltyStop, YoyoExit, DonchianStop, PercentageTrailingStop, StepTrailingStop, RenkoTrailingStop, TypicalPrice, MedianPrice, WeightedClose, LinearRegression, LinRegSlope, AcceleratorOscillator, BalanceOfPower, ChoppinessIndex, TrueRange, ChaikinVolatility, YangZhangVolatility, RogersSatchellVolatility, GarmanKlassVolatility, ParkinsonVolatility, LinRegAngle, BollingerBandwidth, PercentB, NATR, HistoricalVolatility, AroonOscillator, WaveTrend, RWI, Vortex, MassIndex, StochRSI, UltimateOscillator, PPO, Coppock, VWMA, MaEnvelope, AccelerationBands, StarcBands, AtrBands, HurstChannel, LinRegChannel, StandardErrorBands, DoubleBollinger, TtmSqueeze, FractalChaosBands, VwapStdDevBands, ClassicPivots, FibonacciPivots, Camarilla, WoodiePivots, DemarkPivots, WilliamsFractals, ZigZag, TDSetup, TDSequential, TDDeMarker, TDREI, TDPressure, TDCombo, TDCountdown, TDLines, TDRangeProjection, TDDifferential, TDOpen, TDRiskLevel, InverseFisherTransform, DecyclerOscillator, RoofingFilter, EmpiricalModeDecomposition, HT_DCPHASE, HT_TRENDMODE, HilbertDominantCycle, AdaptiveCycle, SineWave, MAMA, FAMA, Ichimoku, HeikinAshi, ValueArea, VolumeProfile, TpoProfile, InitialBalance, OpeningRange, Doji, Hammer, InvertedHammer, HangingMan, ShootingStar, Engulfing, Harami, MorningEveningStar, ThreeSoldiersOrCrows, PiercingDarkCloud, Marubozu, Tweezer, SpinningTop, ThreeInside, ThreeOutside, TwoCrows, UpsideGapTwoCrows, IdenticalThreeCrows, ThreeLineStrike, ThreeStarsInSouth, AbandonedBaby, AdvanceBlock, BeltHold, Breakaway, Counterattack, DojiStar, DragonflyDoji, GravestoneDoji, LongLeggedDoji, RickshawMan, EveningDojiStar, MorningDojiStar, GapSideBySideWhite, HighWave, Hikkake, HikkakeModified, HomingPigeon, OnNeck, InNeck, Thrusting, SeparatingLines, Kicking, KickingByLength, LadderBottom, MatHold, MatchingLow, LongLine, ShortLine, RisingThreeMethods, FallingThreeMethods, UpsideGapThreeMethods, DownsideGapThreeMethods, StalledPattern, StickSandwich, Takuri, ClosingMarubozu, OpeningMarubozu, TasukiGap, UniqueThreeRiver, ConcealingBabySwallow, OrderBookImbalanceTop1, OrderBookImbalanceFull, Microprice, QuotedSpread, DepthSlope, OrderBookImbalanceTopN, SignedVolume, CumulativeVolumeDelta, TradeImbalance, EffectiveSpread, RealizedSpread, KylesLambda, Footprint, FundingRate, FundingRateMean, FundingRateZScore, FundingBasis, OpenInterestDelta, OIPriceDivergence, OIWeighted, LongShortRatio, TakerBuySellRatio, LiquidationFeatures, TermStructureBasis, CalendarSpread, AdvanceDecline, SharpeRatio, SortinoRatio, CalmarRatio, OmegaRatio, MaxDrawdown, AverageDrawdown, DrawdownDuration, PainIndex, ValueAtRisk, ConditionalValueAtRisk, ProfitFactor, GainLossRatio, RecoveryFactor, KellyCriterion, TreynorRatio, InformationRatio, RenkoBars, KagiBars, PointAndFigureBars, Alpha } = nativeBinding
 
 module.exports.version = version
 module.exports.SMA = SMA
@@ -362,10 +362,20 @@ module.exports.PearsonCorrelation = PearsonCorrelation
 module.exports.Beta = Beta
 module.exports.PairwiseBeta = PairwiseBeta
 module.exports.SpearmanCorrelation = SpearmanCorrelation
+module.exports.RollingCorrelation = RollingCorrelation
+module.exports.RollingCovariance = RollingCovariance
+module.exports.OuHalfLife = OuHalfLife
+module.exports.SpreadHurst = SpreadHurst
+module.exports.DistanceSsd = DistanceSsd
+module.exports.BetaNeutralSpread = BetaNeutralSpread
 module.exports.PairSpreadZScore = PairSpreadZScore
 module.exports.LeadLagCrossCorrelation = LeadLagCrossCorrelation
 module.exports.Cointegration = Cointegration
 module.exports.RelativeStrengthAB = RelativeStrengthAB
+module.exports.VarianceRatio = VarianceRatio
+module.exports.GrangerCausality = GrangerCausality
+module.exports.KalmanHedgeRatio = KalmanHedgeRatio
+module.exports.SpreadBollingerBands = SpreadBollingerBands
 module.exports.MACD = MACD
 module.exports.MACDFIX = MACDFIX
 module.exports.MACDEXT = MACDEXT