apt readiness tasks

Included by tasks/stages/01_constructor.yml before the first apt task of a play.

ready.yml is the entry point: it gates the neutralize include on DOCKER_IN_CONTAINER and always waits for the dpkg lock.
neutralize.yml stops and masks the apt-daily units, gated on a running systemd (/run/systemd/system, the sd_booted convention).

flowchart TB
    stage01["01_constructor.yml"]
    ready["ready.yml"]
    incontainer{"DOCKER_IN_CONTAINER?"}
    neutralize["neutralize.yml"]
    sdbooted{"/run/systemd/system exists?"}
    stopmask["stop and mask the apt-daily timers and services"]
    wait["wait for the dpkg lock"]

    stage01 --> ready
    ready --> incontainer
    incontainer -->|"true"| neutralize
    incontainer -->|"false"| wait
    neutralize --> sdbooted
    sdbooted -->|"true"| stopmask
    sdbooted -->|"false"| wait
    stopmask --> wait