Wickra 0.1.0: streaming-first technical indicators

A multi-language technical analysis library: 25 indicators across trend,
momentum, volatility, and volume families, every one a state machine with
O(1) per-tick updates. Batch evaluation is provided by a blanket extension
trait over the streaming primitive, so live trading bots and historical
backtests run the same code path.

What ships in this initial drop:

  crates/wickra-core   - 25 indicators, Indicator/BatchExt/Chain traits,
                          OHLCV types with validation; 171 unit tests,
                          property tests, Wilder/Bollinger textbook tests.
  crates/wickra        - top-level facade + criterion benches for every
                          indicator at 1K/10K/100K series sizes.
  crates/wickra-data   - streaming CSV reader, tick-to-candle aggregator,
                          multi-timeframe resampler, Binance Spot kline
                          WebSocket adapter behind feature live-binance;
                          11 unit + 1 doctest.
  bindings/python      - PyO3 + maturin, NumPy I/O, type stubs (.pyi),
                          56 pytest tests including streaming==batch
                          equivalence, Wilder reference values, lifecycle.
  bindings/node        - napi-rs native module, TypeScript .d.ts
                          auto-generated, 7 node --test cases.
  bindings/wasm        - wasm-bindgen ES module for browser/bundler/Node;
                          interactive HTML demo at examples/index.html.
  examples/            - Python and Rust scripts: backtest, live trading,
                          parallel multi-asset, multi-timeframe, Binance.
  benchmarks/          - cross-library comparison against TA-Lib,
                          pandas-ta, finta, talipp; Wickra wins every
                          category by 11-1030x (batch) and 17x+ streaming.
  .github/workflows/   - CI matrix (Rust + Python + Node + WASM on
                          Linux/macOS/Windows), release pipeline for
                          PyPI wheels and npm.

Indicators (25):
  Trend       SMA EMA WMA DEMA TEMA HMA KAMA
  Momentum    RSI MACD Stochastic CCI ROC WilliamsR ADX MFI TRIX
              AwesomeOscillator Aroon
  Volatility  BollingerBands ATR Keltner Donchian PSAR
  Volume      OBV VWAP (cumulative + rolling)

cargo clippy --workspace --all-targets -D warnings is clean. License: Apache-2.0.

crates/wickra-core/src/error.rs

@@ -0,0 +1,30 @@
+//! Error types used across `wickra-core`.
+
+use thiserror::Error;
+
+/// Errors that can occur when constructing or operating on an indicator.
+#[derive(Debug, Clone, PartialEq, Eq, Error)]
+pub enum Error {
+    /// A period (window length) must be at least one.
+    #[error("period must be greater than zero")]
+    PeriodZero,
+
+    /// A specific minimum period requirement was not met (e.g. MACD needs slow > fast).
+    #[error("invalid period: {message}")]
+    InvalidPeriod { message: &'static str },
+
+    /// A non-finite value (NaN or infinity) was passed where a finite price was expected.
+    #[error("input value must be finite (got NaN or infinity)")]
+    NonFiniteInput,
+
+    /// A candle whose components do not form a valid bar (e.g. high < low) was provided.
+    #[error("invalid candle: {message}")]
+    InvalidCandle { message: &'static str },
+
+    /// A multiplier or factor must be strictly positive.
+    #[error("multiplier must be greater than zero")]
+    NonPositiveMultiplier,
+}
+
+/// Convenience alias for `Result<T, wickra_core::Error>`.
+pub type Result<T> = core::result::Result<T, Error>;