Bundle the access-switch uplinks

ACCESS-3 has two links to DIST-1, but they are operating as separate trunks. A recent change window exposed intermittent forwarding and inconsistent trunk behavior. The payroll access port must not be disturbed while the uplinks are bundled.

Repair access-switch.cfg so only Gi1/0/47 and Gi1/0/48 form LACP channel-group 12 in active mode.

• Port-channel12 must be an enabled trunk described as Uplink to DIST-1, carrying only VLANs 20, 30, and 99 with native VLAN 99.
• Preserve the hostname, VLANs, and payroll access port.