Initial commit: Arb Pulse monolith with CI and optional Fly deploy.

Real-time BTC cross-exchange arbitrage detection (Kraken, Bybit, OKX, Binance)
with React dashboard, GitHub Actions CI, and documented Fly.io deploy workflow.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/infrastructure/time/clock.ts

@@ -0,0 +1,7 @@
+import type { IClock } from "../../domain/ports/ports.js";
+
+export class SystemClock implements IClock {
+  now(): number {
+    return Date.now();
+  }
+}