feat: add exponential backoff retry strategy

Introduce a retry policy with exponential backoff and jitter for extractor and loader errors, with configurable max attempts and delay caps.

internal/app/custom_errors/backoff.go

@@ -0,0 +1,61 @@
+package custom_errors
+
+import (
+	"context"
+	"math/rand"
+	"time"
+)
+
+func computeBackoffDelay(retryCounter int, baseDelayMs int, maxDelayMs int, maxJitterMs int) time.Duration {
+	if retryCounter < 0 {
+		retryCounter = 0
+	}
+
+	delay := max(time.Duration(baseDelayMs)*time.Millisecond, 0)
+
+	maxDelay := time.Duration(maxDelayMs) * time.Millisecond
+	for i := 0; i < retryCounter; i++ {
+		if maxDelayMs > 0 && delay >= maxDelay {
+			delay = maxDelay
+			break
+		}
+		if delay == 0 {
+			break
+		}
+		delay *= 2
+	}
+
+	if maxDelayMs > 0 && delay > maxDelay {
+		delay = maxDelay
+	}
+
+	if maxJitterMs > 0 {
+		jitter := time.Duration(rand.Intn(maxJitterMs+1)) * time.Millisecond
+		delay += jitter
+	}
+
+	if delay < 0 {
+		delay = 0
+	}
+
+	return delay
+}
+
+func requeueWithBackoff(ctx context.Context, delay time.Duration, enqueue func()) {
+	if delay <= 0 {
+		enqueue()
+		return
+	}
+
+	go func() {
+		timer := time.NewTimer(delay)
+		defer timer.Stop()
+
+		select {
+		case <-ctx.Done():
+			return
+		case <-timer.C:
+			enqueue()
+		}
+	}()
+}