feat: Family 02 Momentum Oscillators — RVI / PGO / KST / SMI / Laguerre / Connors / Inertia (#40)

* feat(rvi): add Relative Vigor Index

Dorsey's RVI = SMA(close - open, period) / SMA(high - low, period) over
a rolling window of period candles. Candle input, single parameter
period (default 10). Positive on average-bullish windows, negative on
average-bearish. Holds the previous value if the entire window has
zero range (denominator undefined).

Reference: Donald Dorsey, also pandas-ta rvi.

Touchpoints: rvi.rs + mod.rs + lib.rs re-export, PyRvi + __init__.py
+ test_new_indicators CANDLE_SCALAR + test_known_values reference,
RviNode (4-column OHLC batch) + index.d.ts/index.js + indicators.test
.js factory + reference, WasmRvi + make_candle_ohlc helper, candle-fuzz
target + criterion bench, README + CHANGELOG.

* feat(pgo): add Pretty Good Oscillator

Mark Johnson's PGO = (close - SMA(close, period)) / EMA(TR, period).
Counts roughly how many ATR-equivalents the close sits from its
period-bar mean. Candle input, single parameter period (default 14).
Johnson's heuristic uses +3/-3 crossings as entry signals.

Touchpoints: pgo.rs + mod.rs + lib.rs re-export, PyPgo + __init__.py
+ test_new_indicators CANDLE_SCALAR + test_known_values flat-close
reference, PgoNode (h/l/c) + index.d.ts/index.js + indicators.test.js
factory + reference, WasmPgo, candle-fuzz target + bench, README +
CHANGELOG.

* feat(kst): add Know Sure Thing (Pring)

Pring's long-horizon momentum oscillator: weighted sum of four
SMA-smoothed ROC series with fixed weights 1, 2, 3, 4, plus an SMA
signal line. Nine parameters (four ROC periods, four SMA periods, one
signal period); classic() applies Pring's recommended defaults.
Multi-output indicator emitting KstOutput { kst, signal }.

Touchpoints: kst.rs + mod.rs + lib.rs re-export, PyKst + __init__.py
+ test_new_indicators MULTI + test_known_values flat-input reference,
KstNode + KstValue + index.d.ts/index.js + indicators.test.js multi
factory + reference, WasmKst (manual JsValue object), scalar-fuzz
target (handled outside the f64-output drive helper), README +
CHANGELOG.

* feat(smi): add Stochastic Momentum Index (Blau)

Blau's doubly-EMA-smoothed bounded oscillator: measures the close's
displacement from the centre of the recent high-low range, scaled by
the smoothed range. Candle input, three parameters (period, d_period,
d2_period) with defaults 5 / 3 / 3.

Internally feeds both the displacement-EMA stack and the range-EMA
stack on every candle so they warm up in parallel (gating either
behind the other starves the second by one input).

Touchpoints: smi.rs + mod.rs + lib.rs re-export, PySmi + __init__.py
+ test_new_indicators CANDLE_SCALAR + test_known_values flat-input
reference, SmiNode + index.d.ts/index.js + indicators.test.js factory
+ reference, WasmSmi, candle-fuzz target, README + CHANGELOG.

* feat(laguerre-rsi): add Ehlers Laguerre RSI

Four-stage Laguerre polynomial filter wrapped in an RSI-style up/down
accumulator. Single gamma in [0, 1] (default 0.5) trades lag for
smoothness. State is seeded by setting all four L_i to the first input
so a constant series stays at the neutral 50. Output clamped to
[0, 100] to absorb floating-point rounding.

Reference: Ehlers, Time Warp - Without Space Travel, 2002.

Touchpoints: laguerre_rsi.rs + mod.rs + lib.rs re-export, PyLaguerreRsi
+ __init__.py + test_new_indicators SCALAR + test_known_values neutral
reference, LaguerreRsiNode + index.d.ts/index.js + indicators.test.js
factory + reference, WasmLaguerreRsi via scalar macro, scalar-fuzz
target, README + CHANGELOG.

* feat(connors-rsi): add Connors RSI (CRSI)

Larry Connors' 3-component aggregate: RSI(close), RSI(streak), and
PercentRank of the 1-period return over the last period_rank returns.
Each component is bounded in [0, 100] so the aggregate is too.
Three parameters (period_rsi, period_streak, period_rank) with
defaults 3 / 2 / 100. Streak tracks consecutive up/down runs (resets
to 0 on unchanged close).

Touchpoints: connors_rsi.rs + mod.rs + lib.rs re-export, PyConnorsRsi
+ __init__.py + test_new_indicators SCALAR + test_known_values bounded
reference, ConnorsRsiNode + index.d.ts/index.js + indicators.test.js
factory + reference, WasmConnorsRsi via scalar macro, scalar-fuzz
target, README + CHANGELOG.

* feat(inertia): add Dorsey Inertia (RVI + LinReg)

Donald Dorsey's Inertia — a LinearRegression smoothing of the RVI
series. Endpoint of an n-bar least-squares fit of RVI is the indicator
reading. Preserves trend direction while damping the ratio. Candle
input, two parameters (rvi_period, linreg_period) with defaults 14 / 20.

Touchpoints: inertia.rs + mod.rs + lib.rs re-export, PyInertia +
__init__.py + test_new_indicators CANDLE_SCALAR + test_known_values
constant reference, InertiaNode (4-column OHLC batch) + index.d.ts /
index.js + indicators.test.js factory + reference, WasmInertia,
candle-fuzz target, README + CHANGELOG.

* test(kst): Move KST out of MULTI dict (it is scalar-input)

KST sits in the MULTI dict (candle-input, multi-output) but its
update() takes a single f64, not a candle tuple. The shared streaming
loop in test_multi_streaming_matches_batch fed the OHLCV tuple in,
which crashed with `TypeError: argument 'value': must be real number,
not tuple` on every Python matrix entry.

Split into a new MULTI_SCALAR_INPUT dict with its own test function
that feeds the close-price stream as floats. KST is currently the
only such indicator; structure is ready for future scalar-input
multi-output additions (e.g. some MACD-shaped indicators).

* test(coverage): Cover SMI zero-range and ConnorsRsi zero-prev cold paths

codecov/patch on PR 40 flagged two uncovered defensive branches:
- SMI returns self.current early when the smoothed range collapses to
  zero (`r2 <= 0.0`) so the formula stays defined. Exercised by feeding
  bars where high == low.
- ConnorsRsi skips the ROC ring-buffer update when the previous price
  is exactly zero so the divide-by-zero in `(input - prev) / prev` is
  impossible. Exercised by seeding the first bar at 0.0.

crates/wickra-core/src/indicators/mod.rs

@@ -25,6 +25,7 @@ mod chandelier_exit;
 mod choppiness_index;
 mod cmf;
 mod cmo;
+mod connors_rsi;
 mod coppock;
 mod dema;
 mod donchian;
@@ -36,9 +37,12 @@ mod force_index;
 mod frama;
 mod historical_volatility;
 mod hma;
+mod inertia;
 mod jma;
 mod kama;
 mod keltner;
+mod kst;
+mod laguerre_rsi;
 mod linreg;
 mod linreg_angle;
 mod linreg_slope;
@@ -51,12 +55,15 @@ mod mom;
 mod natr;
 mod obv;
 mod percent_b;
+mod pgo;
 mod pmo;
 mod ppo;
 mod psar;
 mod roc;
 mod rsi;
+mod rvi;
 mod sma;
+mod smi;
 mod smma;
 mod std_dev;
 mod stoch_rsi;
@@ -104,6 +111,7 @@ pub use chandelier_exit::{ChandelierExit, ChandelierExitOutput};
 pub use choppiness_index::ChoppinessIndex;
 pub use cmf::ChaikinMoneyFlow;
 pub use cmo::Cmo;
+pub use connors_rsi::ConnorsRsi;
 pub use coppock::Coppock;
 pub use dema::Dema;
 pub use donchian::{Donchian, DonchianOutput};
@@ -115,9 +123,12 @@ pub use force_index::ForceIndex;
 pub use frama::Frama;
 pub use historical_volatility::HistoricalVolatility;
 pub use hma::Hma;
+pub use inertia::Inertia;
 pub use jma::Jma;
 pub use kama::Kama;
 pub use keltner::{Keltner, KeltnerOutput};
+pub use kst::{Kst, KstOutput};
+pub use laguerre_rsi::LaguerreRsi;
 pub use linreg::LinearRegression;
 pub use linreg_angle::LinRegAngle;
 pub use linreg_slope::LinRegSlope;
@@ -130,12 +141,15 @@ pub use mom::Mom;
 pub use natr::Natr;
 pub use obv::Obv;
 pub use percent_b::PercentB;
+pub use pgo::Pgo;
 pub use pmo::Pmo;
 pub use ppo::Ppo;
 pub use psar::Psar;
 pub use roc::Roc;
 pub use rsi::Rsi;
+pub use rvi::Rvi;
 pub use sma::Sma;
+pub use smi::Smi;
 pub use smma::Smma;
 pub use std_dev::StdDev;
 pub use stoch_rsi::StochRsi;