a1c646ae7c
The seven BTCUSDT OHLCV datasets used to live under crates/wickra/examples/data/, which buried them inside a Rust crate even though the Node backtest example and the upcoming Rust/Node/WASM example restructure need to reach them too. Move them to the workspace-level examples/data/ so every language's examples can resolve the same path. The bench (crates/wickra/benches/indicators.rs), the example_data integration test, fetch_btcusdt.rs and the Node backtest example all take the new ../../examples/data/ path; Data-Layer.md, examples/README.md and the CHANGELOG entry are updated to match. No data file content changes.