Fix FreeBSD build by defining createTokenFile

[kinchan]

Need issues #1365 patch first.

Summary

Building cloudflared on FreeBSD currently fails with:

cmd/cloudflared/common_service.go:56:12: undefined: createTokenFile

This worked around mid-July 2026, but no longer builds on the current HEAD.

Environment

• OS: FreeBSD 14 and 15 (amd64)
• Build command:

gmake cloudflared

Cause

createTokenFile is defined for Linux, macOS, and Windows, but there is no corresponding definition for FreeBSD.

Current implementations:

• cmd/cloudflared/linux_service.go
• cmd/cloudflared/macos_service.go
• cmd/cloudflared/windows_service.go

FreeBSD is missing an equivalent definition.

Fix

Adding the following file restores the build successfully:

cmd/cloudflared/freebsd_service.go

//go:build freebsd

package main

var createTokenFile = createTokenFileUnix

Verification

After adding the file:

• gmake cloudflared completes successfully.
• The resulting cloudflared binary starts correctly.
• Basic tunnel operation has been verified on FreeBSD.

This change only affects FreeBSD builds and does not modify behavior on other platforms.