The Docker daemon refuses any endpoint settings on the default bridge network and `docker compose` unconditionally attaches the service name as an alias on every joined network, so combining bridge with user-defined networks via compose's `networks:` block is impossible. When `vector-networks` is set, the compose template now joins only the configured networks; outbound to external sinks still works through user-defined network NAT. Additionally, `vector-image` and `vector-networks` are both global-only but `common.CommandPropertySet` silently accepts them at app level by merging global-only keys into the valid-property set, so both now reject explicitly in `validateSetValue`.
Adds a new global `vector-networks` property on the logs plugin that takes a comma-separated list of Docker networks. When set, the rendered compose file declares each network plus `bridge` as external and joins them on the vector service, so `docker compose up` reconciles attachments on every `logs:vector-start`. When unset, the existing `network_mode: bridge` template is preserved unchanged. The value is validated against `docker network inspect` at set time, rejects the reserved `bridge` entry, and is surfaced in `dokku logs:report` via `--logs-vector-global-networks`.
Using compose instead of manual docker calls allows folks to customize the vector container by using a custom compose.yml template file. This opens us up to more customizations while aligning container management with how we do other external containers (such as for the proxy plugins).
Refs #5784
