F13a: add Accelerator Oscillator, Balance of Power, Choppiness Index and Vertical Horizontal Filter

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

- Rust core: accelerator_oscillator.rs (AcceleratorOscillator — AO minus a
  short SMA of itself), balance_of_power.rs (BalanceOfPower — per-bar
  (close-open)/(high-low)), choppiness_index.rs (ChoppinessIndex — summed
  true range over the high-low span, log-scaled) and
  vertical_horizontal_filter.rs (VerticalHorizontalFilter — net move over
  total move). 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
  (BalanceOfPower carries an explicit open column; VHF rides the scalar
  macros) 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 in F13c once F13b's four indicators are in.

cargo fmt + clippy (core/wickra/data/wasm/node) clean; 481 core tests,
25 data tests and 70 doctests green.

bindings/node/src/lib.rs

@@ -110,6 +110,11 @@ node_scalar_indicator!(CmoNode, "CMO", wc::Cmo);
 node_scalar_indicator!(DpoNode, "DPO", wc::Dpo);
 node_scalar_indicator!(StdDevNode, "StdDev", wc::StdDev);
 node_scalar_indicator!(UlcerIndexNode, "UlcerIndex", wc::UlcerIndex);
+node_scalar_indicator!(
+    VerticalHorizontalFilterNode,
+    "VerticalHorizontalFilter",
+    wc::VerticalHorizontalFilter
+);
 
 // ============================== MACD ==============================
 
@@ -2034,6 +2039,183 @@ impl LinRegSlopeNode {
     }
 }
 
+// ============================== Accelerator Oscillator ==============================
+
+#[napi(js_name = "AcceleratorOscillator")]
+pub struct AcceleratorOscillatorNode {
+    inner: wc::AcceleratorOscillator,
+}
+
+#[napi]
+impl AcceleratorOscillatorNode {
+    #[napi(constructor)]
+    pub fn new(ao_fast: u32, ao_slow: u32, signal_period: u32) -> napi::Result<Self> {
+        Ok(Self {
+            inner: wc::AcceleratorOscillator::new(
+                ao_fast as usize,
+                ao_slow as usize,
+                signal_period as usize,
+            )
+            .map_err(map_err)?,
+        })
+    }
+    #[napi]
+    pub fn update(&mut self, high: f64, low: f64) -> napi::Result<Option<f64>> {
+        Ok(self.inner.update(cnd(high, low, low, 0.0)?))
+    }
+    #[napi]
+    pub fn batch(&mut self, high: Vec<f64>, low: Vec<f64>) -> napi::Result<Vec<f64>> {
+        if high.len() != low.len() {
+            return Err(NapiError::from_reason(
+                "high and low must be equal length".to_string(),
+            ));
+        }
+        let mut out = Vec::with_capacity(high.len());
+        for i in 0..high.len() {
+            out.push(
+                self.inner
+                    .update(cnd(high[i], low[i], low[i], 0.0)?)
+                    .unwrap_or(f64::NAN),
+            );
+        }
+        Ok(out)
+    }
+    #[napi]
+    pub fn reset(&mut self) {
+        self.inner.reset();
+    }
+    #[napi(js_name = "isReady")]
+    pub fn is_ready(&self) -> bool {
+        self.inner.is_ready()
+    }
+    #[napi(js_name = "warmupPeriod")]
+    pub fn warmup_period(&self) -> u32 {
+        self.inner.warmup_period() as u32
+    }
+}
+
+// ============================== Balance of Power ==============================
+
+#[napi(js_name = "BalanceOfPower")]
+pub struct BalanceOfPowerNode {
+    inner: wc::BalanceOfPower,
+}
+
+impl Default for BalanceOfPowerNode {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[napi]
+impl BalanceOfPowerNode {
+    #[napi(constructor)]
+    pub fn new() -> Self {
+        Self {
+            inner: wc::BalanceOfPower::new(),
+        }
+    }
+    #[napi]
+    pub fn update(
+        &mut self,
+        open: f64,
+        high: f64,
+        low: f64,
+        close: f64,
+    ) -> napi::Result<Option<f64>> {
+        let candle = wc::Candle::new(open, high, low, close, 0.0, 0).map_err(map_err)?;
+        Ok(self.inner.update(candle))
+    }
+    #[napi]
+    pub fn batch(
+        &mut self,
+        open: Vec<f64>,
+        high: Vec<f64>,
+        low: Vec<f64>,
+        close: Vec<f64>,
+    ) -> napi::Result<Vec<f64>> {
+        if open.len() != high.len() || high.len() != low.len() || low.len() != close.len() {
+            return Err(NapiError::from_reason(
+                "open, high, low, close must be equal length".to_string(),
+            ));
+        }
+        let mut out = Vec::with_capacity(open.len());
+        for i in 0..open.len() {
+            let candle =
+                wc::Candle::new(open[i], high[i], low[i], close[i], 0.0, 0).map_err(map_err)?;
+            out.push(self.inner.update(candle).unwrap_or(f64::NAN));
+        }
+        Ok(out)
+    }
+    #[napi]
+    pub fn reset(&mut self) {
+        self.inner.reset();
+    }
+    #[napi(js_name = "isReady")]
+    pub fn is_ready(&self) -> bool {
+        self.inner.is_ready()
+    }
+    #[napi(js_name = "warmupPeriod")]
+    pub fn warmup_period(&self) -> u32 {
+        self.inner.warmup_period() as u32
+    }
+}
+
+// ============================== Choppiness Index ==============================
+
+#[napi(js_name = "ChoppinessIndex")]
+pub struct ChoppinessIndexNode {
+    inner: wc::ChoppinessIndex,
+}
+
+#[napi]
+impl ChoppinessIndexNode {
+    #[napi(constructor)]
+    pub fn new(period: u32) -> napi::Result<Self> {
+        Ok(Self {
+            inner: wc::ChoppinessIndex::new(period as usize).map_err(map_err)?,
+        })
+    }
+    #[napi]
+    pub fn update(&mut self, high: f64, low: f64, close: f64) -> napi::Result<Option<f64>> {
+        Ok(self.inner.update(cnd(high, low, close, 0.0)?))
+    }
+    #[napi]
+    pub fn batch(
+        &mut self,
+        high: Vec<f64>,
+        low: Vec<f64>,
+        close: Vec<f64>,
+    ) -> napi::Result<Vec<f64>> {
+        if high.len() != low.len() || low.len() != close.len() {
+            return Err(NapiError::from_reason(
+                "high, low, close must be equal length".to_string(),
+            ));
+        }
+        let mut out = Vec::with_capacity(high.len());
+        for i in 0..high.len() {
+            out.push(
+                self.inner
+                    .update(cnd(high[i], low[i], close[i], 0.0)?)
+                    .unwrap_or(f64::NAN),
+            );
+        }
+        Ok(out)
+    }
+    #[napi]
+    pub fn reset(&mut self) {
+        self.inner.reset();
+    }
+    #[napi(js_name = "isReady")]
+    pub fn is_ready(&self) -> bool {
+        self.inner.is_ready()
+    }
+    #[napi(js_name = "warmupPeriod")]
+    pub fn warmup_period(&self) -> u32 {
+        self.inner.warmup_period() as u32
+    }
+}
+
 // ============================== Bollinger Bandwidth ==============================
 
 #[napi(js_name = "BollingerBandwidth")]