Batch search webhook results

Search webhook results for multiple parcels at once. Use this to retrieve final results of registered webhooks.

Search methods:

• Search by carrier + trackingNumber
• Search by clientId
• Both methods can be used simultaneously

How it works:

• Searches using trackingIndex/clientIdIndex fields in the tracking_requests collection
• Returns only the latest document when multiple documents exist for the same tracking number
• Batch processed due to Firestore array-contains-any limit (10) (up to 10 queries for 100 items)

Free API - does not count towards usage quota.