fix: use shared webhook retry delay helper

src/modules/webhooks/webhook.service.test.ts

@@ -137,6 +137,7 @@ describe('dispatchWebhookEvent', () => {
    beforeEach(() => {
       jest.useFakeTimers();
       global.fetch = jest.fn();
+      jest.spyOn(Math, 'random').mockReturnValue(0);
    });
 
    afterEach(() => {
@@ -313,17 +314,25 @@ describe('dispatchWebhookEvent', () => {
          }),
          'Webhook delivery failed, retrying'
       );
-      expect(logger.error).toHaveBeenCalledWith(
+      const exhaustionLogCalls = (logger.error as jest.Mock).mock.calls.filter(
+         ([, message]) =>
+            message === 'Webhook delivery exhausted all retries, flagged as failing'
+      );
+      expect(exhaustionLogCalls).toHaveLength(1);
+
+      const [exhaustionLogFields] = exhaustionLogCalls[0];
+      expect(exhaustionLogFields).toEqual(
          expect.objectContaining({
             webhook_id: 'wh-1',
             creator_id: 'creator-1',
             event_type: 'sell',
             total_attempts: envConfig.WEBHOOK_RETRY_MAX_ATTEMPTS,
             last_error_code: 'Network error',
             flagged_at: expect.any(String),
-         }),
-         'Webhook delivery exhausted all retries, flagged as failing'
+         })
       );
+      expect(exhaustionLogFields.callback_url).toBeUndefined();
+      expect(exhaustionLogFields.callbackUrl).toBeUndefined();
 
       // Verify attempt log was emitted for every retry attempt (success: false, response_status: null)
       for (let attempt = 1; attempt <= envConfig.WEBHOOK_RETRY_MAX_ATTEMPTS; attempt++) {

src/modules/webhooks/webhook.service.ts

@@ -2,6 +2,7 @@ import { prisma } from '../../utils/prisma.utils';
 import { logger } from '../../utils/logger.utils';
 import { envConfig } from '../../config';
 import { maskWebhookUrl } from '../../utils/webhook-mask.utils';
+import { computeRetryDelay } from '../../utils/retry-delay.utils';
 import { buildWebhookPayload } from './webhook-payload.utils';
 import type {
     CreateWebhookInput,
@@ -193,6 +194,7 @@ async function attemptDelivery(
    attempt = 1
 ): Promise<void> {
    const maxAttempts = envConfig.WEBHOOK_RETRY_MAX_ATTEMPTS;
+   const maxDelayMs = 30_000;
    const startTime = Date.now();
    let responseStatus: number | null = null;
    let responseTimeMs = 0;
@@ -282,7 +284,11 @@ async function attemptDelivery(
       });
 
       if (attempt < maxAttempts) {
-         const delay = Math.pow(2, attempt) * 1000;
+         const delay = computeRetryDelay(
+            attempt,
+            envConfig.WEBHOOK_RETRY_BASE_DELAY_MS,
+            maxDelayMs
+         );
          logger.warn(
             {
                webhook_id: webhookId,