- Added a unified `uri` field to webhookSubscriptionCreate and webhookSubscriptionUpdate mutations supporting HTTPS URLs, Google Pub/Sub URIs, and Amazon EventBridge ARNs
- Updated WebhookSubscription type and webhookSubscriptions query to include and filter by the new `uri` field
- Deprecated endpoint‑specific mutations (eventBridgeWebhookSubscriptionCreate/Update, pubSubWebhookSubscriptionCreate/Update) and the `callbackUrl` field in favor of the unified `uri` approach