Introduces the `decnet webhook` long-running worker that consumes the
internal bus and POSTs matching events to configured subscriptions.
Design: one task per (subscription, pattern) pair. Each task opens
its own bus subscription, iterates events, and dispatches via the
shared deliver() client. No intermediate queue, no in-memory filter
matching — the bus's own pattern matcher is the filter. Reloads on
`system.webhook.subscriptions_changed` signals from the CRUD router,
with a 60s fallback timer in case a signal is lost.
Shutdown propagates via CancelledError on the outer task; all inner
subscription tasks are cancelled and awaited in a finally block.
Bus unavailable → worker stays up in idle mode per the DEBT-031
pattern, logging one warning.
Registered as a master-only CLI command (agents don't configure
webhooks — the subscription store lives on master). systemd unit
mirrors the profiler template; added to decnet.target Wants= list so
`systemctl start decnet.target` brings it up alongside everything
else. `decnet init` auto-picks up the new .service.j2 via its
existing `glob("decnet-*.service.j2")` sweep.
Adds the five missing worker units plus a grouping target so
`systemctl start decnet.target` brings the whole fleet up in order.
Sniffer gets CAP_NET_RAW for scapy; collector and mutator join the
docker supplementary group for docker.sock access. Repoints
Documentation= across all existing units to the canonical
git.resacachile.cl wiki.
