chore(cloudflare): migrate customhostname to v5

docs/tutorials/cloudflare.md

@@ -4,37 +4,6 @@ This tutorial describes how to setup ExternalDNS for usage within a Kubernetes c
 
 Make sure to use **>=0.4.2** version of ExternalDNS for this tutorial.
 
-## CloudFlare SDK Migration Status
-
-ExternalDNS is currently migrating from the legacy CloudFlare Go SDK v0 to the modern v4 SDK to improve performance, reliability, and access to newer CloudFlare features. The migration status is:
-
-**✅ Fully migrated to v4 SDK:**
-
-- Zone management (listing, filtering, pagination)
-- Zone details retrieval (`GetZone`)
-- Zone ID lookup by name (`ZoneIDByName`)
-- Zone plan detection (fully v4 implementation)
-- Regional services (data localization)
-
-**🔄 Still using legacy v0 SDK:**
-
-- DNS record management (create, update, delete records)
-- Custom hostnames
-- Proxied records
-
-This mixed approach ensures continued functionality while gradually modernizing the codebase. Users should not experience any breaking changes during this transition.
-
-### SDK Dependencies
-
-ExternalDNS currently uses:
-
-- **cloudflare-go v0.115.0+**: Legacy SDK for DNS records, custom hostnames, and proxied record features
-- **cloudflare-go/v4 v4.6.0+**: Modern SDK for all zone management and regional services operations
-
-Zone management has been fully migrated to the v4 SDK, providing improved performance and reliability.
-
-Both SDKs are automatically managed as Go module dependencies and require no special configuration from users.
-
 ## Creating a Cloudflare DNS zone
 
 We highly recommend to read this tutorial if you haven't used Cloudflare before:
@@ -384,8 +353,6 @@ The custom hostname DNS must resolve to the Cloudflare DNS record (`external-dns
 
 Requires [Cloudflare for SaaS](https://developers.cloudflare.com/cloudflare-for-platforms/cloudflare-for-saas/) product and "SSL and Certificates" API permission.
 
-**Note:** Due to using the legacy cloudflare-go v0 API for custom hostname management, the custom hostname page size is fixed at 50. This limitation will be addressed in a future migration to the v4 SDK.
-
 ## Setting Cloudflare DNS Record Tags
 
 Cloudflare allows you to add descriptive tags to DNS records. This can be useful for organizing your records.