Run nix.gc weekly to delete generations older than 14 days, and limit
lanzaboote to 10 entries so the ESP menu never lists generations whose
store paths have already been collected.
Assisted-by: Claude:opus-5-5
The in-tree amdxdna driver on LTS 6.18 is too old for FastFlowLM:
flm validate reports kernel_ok=false and the driver loads NPU firmware
1.0.0.63, while FLM needs 1.1.0.0 or newer. The 7.x driver loads
npu_7.sbin (1.1.2.64), and /dev/accel/accel0 is present on 7.2.11.
Assisted-by: Claude:opus-5-5
