broker: a module account scopes its tool serve queues and mesh.rpc (ADR 0052)

CreateModuleAccount now also grants serve.<module>.* (declare, bind, consume its
own tool queues) and mesh.rpc (bind them on, publish replies) — so a module can
serve its tools and reply, scoped to exactly its own, and no other module's. The
broker tests still hold a module out of another's queue.

internal/broker/management.go

@@ -92,20 +92,27 @@ func ModuleQueueFor(node, module string) string { return node + "." + module + "
 func modulePermissions(node, module string, emits, consumes []string) (configure, write, read string) {
 	queue := regexp.QuoteMeta(ModuleQueueFor(node, module))
 	events := regexp.QuoteMeta(EventsExchangeName)
+	rpc := regexp.QuoteMeta(RPCExchangeName)
+	// A module serves each of its tools on its own queue, namespaced by the module (novox/hq
+	// ADR 0052) — serve.<module>.<tool> — so the account may declare, bind and read exactly its own,
+	// and no other module's.
+	serve := "serve\\." + regexp.QuoteMeta(module) + "\\..*"
 
-	// Declare only its own queue.
-	configure = "^" + queue + "$"
+	// Declare its own events queue and its own tool serve queues.
+	configure = "^(" + queue + "|" + serve + ")$"
 
-	// Write to its own queue — binding a queue to an exchange is a write on the queue — and to the
-	// events exchange only if it emits.
-	writes := []string{queue}
+	// Write to bind its queue and serve queues (binding is a write on the queue), and to the RPC
+	// exchange to publish replies (ADR 0052: replies ride mesh.rpc, never the default exchange, which
+	// would let it publish into any queue). To the events exchange only if it emits.
+	writes := []string{queue, serve, rpc}
 	if len(emits) > 0 {
 		writes = append(writes, events)
 	}
 	write = "^(" + strings.Join(writes, "|") + ")$"
 
-	// Read its own queue to consume it, and the events exchange to bind onto, only if it consumes.
-	reads := []string{queue}
+	// Read its own queue and serve queues to consume them, and the RPC exchange to bind its serve
+	// queues onto. The events exchange to bind onto only if it consumes.
+	reads := []string{queue, serve, rpc}
 	if len(consumes) > 0 {
 		reads = append(reads, events)
 	}