VyOS rolling Fullcone kernel

Builds the current VyOS rolling kernel with the same Fullcone patch set used by homerouter/aports:

• 0021-nft_fullcone.patch adds the nftables fullcone expression.
• 982-add-bcm-fullconenat-support.patch and 983-bcm-fullconenat-mod-nft-masq.patch add masquerade brcmfullcone.

The repository keeps the original shell build flow, updated from current VyOS:

• build-kernel.sh builds the rolling kernel with the Fullcone patches.
• build-intel-qat.sh builds and signs the matching Intel QAT driver modules.
• build-linux-firmware.sh packages firmware selected from the built drivers.

A QEMU boot test exercises both Fullcone paths before all generated .deb packages are released.

Run Build VyOS rolling Fullcone kernel from the Actions tab. No repository secrets are required.