feat(data): native live Binance kline feed in 9 languages (+ 3d/1M intervals) (#313)

* feat(data): C-ABI Binance feed + Go binding (F4 wip)

C ABI exposes the existing async BinanceKlineStream (tokio + TLS, auto-reconnect,
mock-server-tested in wickra-data) through a blocking poll: wickra_binance_connect
/ _next(out, timeout_ms) -> {1 event, 0 timeout, -1 closed} / _close / _free over
an opaque BinanceStream that owns a current-thread runtime. WickraKlineEvent
carries OHLCV + open_time + is_closed + a 16-byte symbol buffer. `live-binance`
is now a default feature of wickra-c (the published DLL ships the feed; the wasm
build drops it via --no-default-features).

Go: NewBinanceFeed(symbols, interval, baseURL) + Next(timeout) + Close, with a
deterministic error-path smoke (the connect->event pipeline is covered by the
Rust mock-WS-server tests).

* feat(data): Binance feed C# + Java bindings (F4 wip)

C#: BinanceFeed(symbols, interval, baseUrl?) + Next(timeout) -> KlineEvent? +
Dispose; bespoke WickraKlineEvent native struct (fixed symbol buffer + byte
is_closed) since the scalar struct parser can't model it. `char` maps to `byte`
for the const char* params.

Java: BinanceFeed + KlineEvent record + BinanceInterval enum over Panama FFM;
the event is read at hand-computed offsets (symbol@0, doubles@16..48,
open_time@56, is_closed@64; 72-byte struct). Both with deterministic error-path
smokes (pipeline covered by the Rust mock-WS-server tests).

* feat(data): Binance feed R binding (F4 wip)

R: BinanceFeed(symbols, interval, base_url) + binance_next(feed, timeout_ms) ->
named list | NULL + binance_close, via bespoke .Call glue (wk_binance_*). The
glue + its registration entries are gated out of the Emscripten/wasm build
(#ifndef __EMSCRIPTEN__) since r-universe/webR has no raw sockets. NAMESPACE
exports added by hand (roxygen2 not installed locally). Deterministic error-path
smoke; pipeline covered by the Rust mock-WS-server tests.

* feat(data): native Binance feed for Node + Python; CHANGELOG (F4 complete)

Node (napi) BinanceFeed: new(symbols, interval, baseUrl?) + next(timeoutMs) ->
KlineEvent | null + close. Python (pyo3) BinanceFeed: same, with next releasing
the GIL (py.detach) while it waits. Both drive the mock-server-tested async
BinanceKlineStream on a single-thread tokio runtime (blocking poll); wickra-data
gains the live-binance feature + tokio in each binding.

Completes F4: the live Binance kline feed is now native in all 9 languages
(WASM excluded), with no third-party WebSocket client in any of them.

bindings/node/src/lib.rs

@@ -21884,6 +21884,138 @@ pub struct CandleValue {
     pub timestamp: f64,
 }
 
+/// One event from the live Binance feed.
+#[napi(object)]
+pub struct KlineEvent {
+    pub symbol: String,
+    pub open: f64,
+    pub high: f64,
+    pub low: f64,
+    pub close: f64,
+    pub volume: f64,
+    pub open_time: f64,
+    pub is_closed: bool,
+}
+
+/// Map a `u8` interval code (`0..=15`, the `Interval` declaration order) to the
+/// feed interval.
+fn binance_interval(code: u8) -> Option<wickra_data::live::binance::Interval> {
+    use wickra_data::live::binance::Interval;
+    Some(match code {
+        0 => Interval::OneSecond,
+        1 => Interval::OneMinute,
+        2 => Interval::ThreeMinutes,
+        3 => Interval::FiveMinutes,
+        4 => Interval::FifteenMinutes,
+        5 => Interval::ThirtyMinutes,
+        6 => Interval::OneHour,
+        7 => Interval::TwoHours,
+        8 => Interval::FourHours,
+        9 => Interval::SixHours,
+        10 => Interval::EightHours,
+        11 => Interval::TwelveHours,
+        12 => Interval::OneDay,
+        13 => Interval::ThreeDays,
+        14 => Interval::OneWeek,
+        15 => Interval::OneMonth,
+        _ => return None,
+    })
+}
+
+/// A live Binance kline feed. `next` is a blocking poll (it waits up to the
+/// timeout on the calling thread) driving the mock-server-tested wickra-data
+/// `BinanceKlineStream` on a single-thread tokio runtime — use a short timeout in
+/// a loop, or run it on a Worker thread, to keep the event loop responsive.
+#[napi(js_name = "BinanceFeed")]
+pub struct BinanceFeedNode {
+    runtime: tokio::runtime::Runtime,
+    inner: wickra_data::live::binance::BinanceKlineStream,
+}
+
+#[napi]
+impl BinanceFeedNode {
+    /// Connect to Binance's live kline stream for the given comma-separated
+    /// `symbols` (case-insensitive) at the given `interval` code (`0..=15`).
+    /// `baseUrl` overrides the endpoint (omit for production; pass a `ws://` URL
+    /// to target a test server).
+    #[napi(constructor)]
+    pub fn new(symbols: String, interval: u8, base_url: Option<String>) -> napi::Result<Self> {
+        let iv = binance_interval(interval).ok_or_else(|| {
+            NapiError::new(
+                Status::InvalidArg,
+                "unknown interval code (expected 0..=15)",
+            )
+        })?;
+        let symbol_list: Vec<String> = symbols
+            .split(',')
+            .map(str::trim)
+            .filter(|s| !s.is_empty())
+            .map(str::to_owned)
+            .collect();
+        if symbol_list.is_empty() {
+            return Err(NapiError::new(
+                Status::InvalidArg,
+                "at least one symbol is required",
+            ));
+        }
+        let mut config = wickra_data::live::binance::BinanceConfig::default();
+        if let Some(url) = base_url {
+            config.base_url = url;
+        }
+        let runtime = tokio::runtime::Builder::new_current_thread()
+            .enable_all()
+            .build()
+            .map_err(|e| NapiError::new(Status::GenericFailure, e.to_string()))?;
+        let inner = runtime
+            .block_on(
+                wickra_data::live::binance::BinanceKlineStream::connect_with_config(
+                    &symbol_list,
+                    iv,
+                    config,
+                ),
+            )
+            .map_err(map_data_err)?;
+        Ok(Self { runtime, inner })
+    }
+
+    /// Poll for the next kline event, waiting up to `timeoutMs` milliseconds.
+    /// Returns the event, or `null` on timeout (call again). Throws once the
+    /// stream is closed.
+    #[napi]
+    pub fn next(&mut self, timeout_ms: f64) -> napi::Result<Option<KlineEvent>> {
+        let dur = std::time::Duration::from_millis(timeout_ms.max(0.0) as u64);
+        let runtime = &self.runtime;
+        let inner = &mut self.inner;
+        let result = runtime.block_on(tokio::time::timeout(dur, inner.next_event()));
+        match result {
+            Ok(Ok(Some(ev))) => Ok(Some(KlineEvent {
+                symbol: ev.symbol,
+                open: ev.candle.open,
+                high: ev.candle.high,
+                low: ev.candle.low,
+                close: ev.candle.close,
+                volume: ev.candle.volume,
+                #[allow(clippy::cast_precision_loss)]
+                open_time: ev.candle.timestamp as f64,
+                is_closed: ev.is_closed,
+            })),
+            Ok(Ok(None) | Err(_)) => Err(NapiError::new(
+                Status::GenericFailure,
+                "binance feed closed",
+            )),
+            Err(_) => Ok(None),
+        }
+    }
+
+    /// Close the stream; subsequent `next` calls throw.
+    #[napi]
+    pub fn close(&mut self) {
+        let runtime = &self.runtime;
+        let inner = &mut self.inner;
+        let _ = runtime.block_on(inner.close());
+    }
+}
+
 /// Roll trade ticks up into fixed-timeframe OHLCV candles.
 #[napi(js_name = "TickAggregator")]
 pub struct TickAggregatorNode {