The host-side pass could not work for unprivileged GNS3 processes: the
.gns3_perms marker is created root-owned by the container-side touch, and
chowning root-owned files from the host requires root.
Rewrite VendorDockerVM._fix_permissions to run the busybox
record/chmod/chown script inside the container (as root) on the
/gns3volumes bind-mount targets — they exist for the container's whole
lifetime and do not depend on the mount --bind bridge, so a container
restart can no longer make the fix hit the overlay copy. A
stopped/exited container is skipped (logged) instead of restarted; the
next start's pass fixes ownership.
Replace the container-side _fix_permissions for vendor NOS containers with a
host-side pass that walks the node's project directories directly (they are
the Docker bind-mount sources): records mode:uid:gid into .gns3_perms and
chowns to the GNS3 user. No docker exec, no container restart — the base
implementation restarts an exited container just to chown, and after the
restart the mount --bind bridge is gone so it would fix the overlay copy
instead of the host files.
The pass runs at start (after _setup_skip_init_volumes seeds and bridges the
volumes) so the controller can read project files while the node runs, and
again at stop for files written during runtime.
Update docker-exec-console.md: VendorDockerVM architecture, hook points,
class-selection factory, volume-persistence lifecycle, and new
troubleshooting entries.
