Completes the F7 family (Volatility) end to end:
- Rust core: natr.rs (ATR as a percentage of close), std_dev.rs
(rolling population standard deviation), ulcer_index.rs (RMS of
trailing-high drawdowns — downside-only risk), historical_volatility.rs
(annualised sample stddev of log returns). Each with a full Indicator
impl, runnable doctest and reference / constant-series / warmup /
reset / batch==streaming tests.
- Python: PyNatr / PyStdDev / PyUlcerIndex / PyHistoricalVolatility
PyO3 classes + module registration + .pyi stubs.
- Node: StdDevNode / UlcerIndexNode via the scalar macro, explicit
NatrNode and HistoricalVolatilityNode; index.d.ts and index.js updated.
- WASM: WasmStdDev / WasmUlcerIndex / WasmHistoricalVolatility via the
scalar macro, explicit WasmNatr.
- Wiki: Indicator-Natr/StdDev/UlcerIndex/HistoricalVolatility.md plus
rows in Indicators-Overview.md and entries in Home.md.
cargo fmt + clippy (core/wickra/data/wasm/node) clean; 350 core tests,
25 data tests and 49 doctests green.
