F13b: add True Range, Chaikin Volatility, Z-Score and Linear Regression Angle

Second half of the eight indicators that fill out the new family taxonomy.

- Rust core: true_range.rs (TrueRange — the raw single-bar volatility ATR
  averages), chaikin_volatility.rs (ChaikinVolatility — rate of change of a
  smoothed high-low spread), z_score.rs (ZScore — price normalised against
  its rolling mean and standard deviation) and linreg_angle.rs (LinRegAngle
  — the rolling regression slope as a degree angle). Each with a full
  Indicator impl, runnable doctest and reference / property / warmup /
  reset / batch==streaming tests.
- Python / Node / WASM: classes wired through all three bindings (ZScore
  and LinRegAngle ride the scalar macros where possible) plus .pyi stubs
  and __init__.py / __all__ entries.
- Wiki: four new Indicator-*.md pages.

The eight-family taxonomy restructure (Overview / Home / README / folder
layout) lands next in F13c.

cargo fmt + clippy (core/wickra/data/wasm/node) clean; 508 core tests,
25 data tests and 74 doctests green.

bindings/wasm/src/lib.rs

@@ -95,6 +95,8 @@ wasm_scalar_indicator!(WasmPercentB, "PercentB", wc::PercentB, period: usize, mu
 wasm_scalar_indicator!(WasmLinearRegression, "LinearRegression", wc::LinearRegression, period: usize);
 wasm_scalar_indicator!(WasmLinRegSlope, "LinRegSlope", wc::LinRegSlope, period: usize);
 wasm_scalar_indicator!(WasmVerticalHorizontalFilter, "VerticalHorizontalFilter", wc::VerticalHorizontalFilter, period: usize);
+wasm_scalar_indicator!(WasmZScore, "ZScore", wc::ZScore, period: usize);
+wasm_scalar_indicator!(WasmLinRegAngle, "LinRegAngle", wc::LinRegAngle, period: usize);
 
 // ---------- KAMA (three params) ----------
 
@@ -1100,6 +1102,84 @@ impl WasmChoppinessIndex {
     }
 }
 
+#[wasm_bindgen(js_name = TrueRange)]
+pub struct WasmTrueRange {
+    inner: wc::TrueRange,
+}
+
+impl Default for WasmTrueRange {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[wasm_bindgen(js_class = TrueRange)]
+impl WasmTrueRange {
+    #[wasm_bindgen(constructor)]
+    pub fn new() -> WasmTrueRange {
+        Self {
+            inner: wc::TrueRange::new(),
+        }
+    }
+    pub fn update(&mut self, high: f64, low: f64, close: f64) -> Result<Option<f64>, JsError> {
+        let c = make_candle(high, low, close, 0.0)?;
+        Ok(self.inner.update(c))
+    }
+    pub fn batch(
+        &mut self,
+        high: &[f64],
+        low: &[f64],
+        close: &[f64],
+    ) -> Result<Float64Array, JsError> {
+        let n = high.len();
+        if low.len() != n || close.len() != n {
+            return Err(JsError::new("high, low, close must be equal length"));
+        }
+        let mut out = Vec::with_capacity(n);
+        for i in 0..n {
+            let c = make_candle(high[i], low[i], close[i], 0.0)?;
+            out.push(self.inner.update(c).unwrap_or(f64::NAN));
+        }
+        Ok(Float64Array::from(out.as_slice()))
+    }
+    pub fn reset(&mut self) {
+        self.inner.reset();
+    }
+}
+
+#[wasm_bindgen(js_name = ChaikinVolatility)]
+pub struct WasmChaikinVolatility {
+    inner: wc::ChaikinVolatility,
+}
+
+#[wasm_bindgen(js_class = ChaikinVolatility)]
+impl WasmChaikinVolatility {
+    #[wasm_bindgen(constructor)]
+    pub fn new(ema_period: usize, roc_period: usize) -> Result<WasmChaikinVolatility, JsError> {
+        Ok(Self {
+            inner: wc::ChaikinVolatility::new(ema_period, roc_period).map_err(map_err)?,
+        })
+    }
+    pub fn update(&mut self, high: f64, low: f64) -> Result<Option<f64>, JsError> {
+        let c = make_candle(high, low, low, 0.0)?;
+        Ok(self.inner.update(c))
+    }
+    pub fn batch(&mut self, high: &[f64], low: &[f64]) -> Result<Float64Array, JsError> {
+        if high.len() != low.len() {
+            return Err(JsError::new("high and low must be equal length"));
+        }
+        let mut out = Vec::with_capacity(high.len());
+        for i in 0..high.len() {
+            let c = make_candle(high[i], low[i], low[i], 0.0)?;
+            out.push(self.inner.update(c).unwrap_or(f64::NAN));
+        }
+        Ok(Float64Array::from(out.as_slice()))
+    }
+    pub fn reset(&mut self) {
+        self.inner.reset();
+    }
+}
+
 #[wasm_bindgen(js_name = NATR)]
 pub struct WasmNatr {
     inner: wc::Natr,