A module declares its fail2ban jail; the mesh composes them per node (to-be 31)

The mechanism, mirroring Filtering: a module declares Jails (name, failregex,
jail stanza) naming no node/path (ADR 0112); the intrusion-prevention holder
declares Jailing (where composed jails go); the mesh gathers every assigned
module's jails into one jail.d file (a fixed id the fail2ban service restarts
on) plus a filter.d file per jail. A node not running a module has none of its
jails. Tested. Behaviour-neutral until a service module declares a jail — the
per-service content (postgres/mssql/mailu failregex+logpath) is authored next,
against how each container actually logs.

internal/catalogue/declaration.go

@@ -345,6 +345,12 @@ func (r Resolution) compose(with Rendering, owner map[string]string) ([]map[stri
 				"content": filtering, "mode": "0600",
 			})
 		}
+		// The node's fail2ban jails, composed from every module it runs (novox/hq to-be 31), written
+		// where the intrusion-prevention holder owns them. Like the rule set above: gathered from all
+		// modules, written by the one that holds the role.
+		if j := m.Jailing; j != nil {
+			first = append(first, jailsInto(r.Modules, j)...)
+		}
 		if c := m.Certificate; c != nil {
 			if with.Certificate == "" {
 				// Asked for and not issued. Refused rather than skipped: a module that serves TLS