Open Classes (/classes) as admin.

Match types on the form:

`match_type`	`match_value` example
`vendor_class`	option 60 string
`user_class`	option 77 string
`mac_prefix`	`aa:bb:cc`

Create a class, then:

Attach DHCP options to the class (same JSON payload shape as subnet options). Default example on the form is code 43 with {"hex":"0102"}.
On a subnet, set a pool’s class so only matching clients get that range. Class-specific pools are preferred for matching clients. A PC cannot grab a phone/PXE range by asking for that address.

Matching is evaluated on the DHCP data plane from the class row. Keep class names stable; pools store the class id. Classes stay inside their tenant. You cannot delete a class that a pool still uses.

Readonly sees the list and cannot mutate.