refactor(exchange): address review — optional-chain init, trim comments

- call strategy.init via optional chaining instead of an if-guard
- shrink getRecentCandles JSDoc to its first sentence
- drop the getDataset doc comment in @typedtrader/candles

Author: bennycode

packages/candles/src/index.ts

@@ -85,7 +85,6 @@ export const datasets: CandleDataset[] = [
   },
 ];
 
-/** Look up a dataset by its `id` (e.g. `'uptrend-stx'`), or `undefined` if there is no match. */
 export function getDataset(id: string): CandleDataset | undefined {
   return datasets.find(dataset => dataset.id === id);
 }

packages/exchange/src/broker/MarketDataSource.ts

@@ -19,15 +19,7 @@ export abstract class MarketDataSource extends EventEmitter {
 
   /**
    * Fetch the most recent `count` candles of the given interval, oldest first — so a strategy can
-   * say "300 hourly candles" without computing calendar windows itself. This is the `count > 1`
-   * generalization of `getLatestCandle`: same "anchor to the latest real bar" trick, wider window.
-   *
-   * Anchors the window's end to the latest real bar (so market closures — nights, weekends,
-   * holidays — don't leave us with an empty "now" window that never fills) and pins it there while
-   * widening the start backward. `getCandles` already paginates a time window to exhaustion, so each
-   * attempt returns a superset of the previous one — no cross-window dedupe needed. We over-ask and
-   * widen only because `count` bars can span far more wall-clock than `count * interval` once closed
-   * sessions are excluded. Built purely on the abstract `getCandles`/`getLatestCandle`.
+   * say "300 hourly candles" without computing calendar windows itself.
    */
   async getRecentCandles(pair: TradingPair, count: number, intervalInMillis: number): Promise<Candle[]> {
     if (count <= 0) {

packages/exchange/src/trader/TradingSession.ts

@@ -69,9 +69,7 @@ export class TradingSession extends EventEmitter<TradingSessionEventMap> {
       tradingRules,
     };
 
-    if (this.#strategy.init) {
-      await this.#strategy.init(this.#broker, this.#pair);
-    }
+    await this.#strategy.init?.(this.#broker, this.#pair);
 
     // Subscribe to candles only after state is ready
     const openTimeInISO = new Date().toISOString();