F13c: restructure the indicator catalogue into eight families

The original taxonomy was four classical families plus a statistics group,
with the F1-F12 expansion slotted in as sub-categories. This regroups the
whole 71-indicator catalogue into eight top-level families, each with at
least five members:

  Moving Averages (12), Momentum Oscillators (13), Trend & Directional (9),
  Price Oscillators (5), Volatility & Bands (12), Trailing Stops (5),
  Volume (9), Price Statistics (7).

- Wiki: docs/wiki/indicators/ reorganised into eight family folders; all 71
  indicator pages moved with `git mv`. Every internal cross-link is
  normalised to `../<family>/Indicator-X.md`, each page's `Family` field is
  set to its new family, and two pre-existing `../Indicator-Chaining.md`
  links (should have been `../../`) are corrected. A link check confirms
  every relative wiki link resolves.
- Indicators-Overview.md fully rewritten around the eight families;
  Home.md indicator reference and the README family table follow suit.
- Warmup-Periods.md gains the eight F13 indicators; CHANGELOG records the
  46-indicator expansion (25 -> 71) and the eight-family taxonomy.
- Tests: Node indicators.test.js and Python test_new_indicators.py cover
  all eight new indicators (Node 91/91, Python 117/117 green).

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

docs/wiki/indicators/price-oscillators/Indicator-BalanceOfPower.md

@@ -0,0 +1,138 @@
+# BalanceOfPower
+
+> Balance of Power (BOP) — where the bar closed within its range relative
+> to where it opened.
+
+## Quick reference
+
+| Field | Value |
+|-------|-------|
+| Family | Price Oscillators |
+| Input type | `Candle` (uses `open`, `high`, `low`, `close`) |
+| Output type | `f64` |
+| Output range | `[−1, +1]` |
+| Default parameters | none (no parameters) |
+| Warmup period | `1` |
+| Interpretation | Intrabar buyer/seller control; `+1` buyers, `−1` sellers. |
+
+## Formula
+
+```
+BOP = (close − open) / (high − low)
+```
+
+Balance of Power asks a single question per bar: did buyers or sellers win it?
+A bar that opened on its low and closed on its high scores `+1` (buyers in
+total control); the mirror image scores `−1`. It is a stateless per-bar
+reading. A zero-range bar carries no information and yields `0`.
+
+## Parameters
+
+`BalanceOfPower` takes **no parameters** — `BalanceOfPower::new()` in Rust,
+`wickra.BalanceOfPower()` in Python, `new ta.BalanceOfPower()` in Node.
+
+## Inputs / Outputs
+
+From `crates/wickra-core/src/indicators/balance_of_power.rs`:
+
+```rust
+impl Indicator for BalanceOfPower {
+    type Input = Candle;
+    type Output = f64;
+    // update(&mut self, input: Candle) -> Option<f64>
+}
+```
+
+`BalanceOfPower` is a **candle-input** indicator that reads all four of
+`open`, `high`, `low`, `close`. Python's streaming `update` accepts a 6-tuple
+or a dict; the batch helper takes `open`, `high`, `low`, `close` numpy arrays.
+Node and WASM expose `update(open, high, low, close)` and the matching
+`batch`.
+
+## Warmup
+
+`BalanceOfPower::new().warmup_period() == 1`. It is a stateless per-bar
+transform — it emits a value from the very first candle.
+
+## Edge cases
+
+- **Zero-range bar.** `high == low` yields `0` instead of dividing by zero.
+- **Close on high, open on low.** Scores exactly `+1`.
+- **Reset.** `bop.reset()` only clears the `is_ready` flag.
+
+## Examples
+
+### Rust
+
+```rust
+use wickra::{Candle, Indicator, BalanceOfPower};
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let mut bop = BalanceOfPower::new();
+    // open 10, high 14, low 10, close 12 -> (12 - 10) / (14 - 10) = 0.5.
+    let v = bop.update(Candle::new(10.0, 14.0, 10.0, 12.0, 1.0, 0)?);
+    println!("{:?}", v);
+    Ok(())
+}
+```
+
+Output:
+
+```
+Some(0.5)
+```
+
+### Python
+
+```python
+import numpy as np
+import wickra as ta
+
+bop = ta.BalanceOfPower()
+print(bop.batch(
+    np.array([10.0]), np.array([14.0]), np.array([10.0]), np.array([12.0])
+))
+```
+
+Output:
+
+```
+[0.5]
+```
+
+### Node
+
+```javascript
+const ta = require('wickra');
+const bop = new ta.BalanceOfPower();
+console.log(bop.batch([10], [14], [10], [12]));
+```
+
+Output:
+
+```
+[ 0.5 ]
+```
+
+## Interpretation
+
+A BOP holding above zero says buyers are consistently winning the bars — a
+healthy uptrend; below zero is the seller's mirror. Because the raw per-bar
+value is noisy, it is commonly smoothed with a short moving average before
+trading the zero-line crossings, or read for divergence against price.
+
+## Common pitfalls
+
+- **Using the raw value as a trend signal.** Per-bar BOP whipsaws; smooth it.
+- **Feeding it scalar prices.** It needs the full OHLC bar — including `open`.
+
+## References
+
+Balance of Power, popularised by Igor Livshin; the `(close − open) /
+(high − low)` definition is the standard one.
+
+## See also
+
+- [Indicator-AwesomeOscillator.md](../momentum-oscillators/Indicator-AwesomeOscillator.md) — another
+  Bill Williams-era price oscillator.
+- [Indicators-Overview.md](../../Indicators-Overview.md) — the full taxonomy.