One bus: the AMQP transport is gone from the controller

The mesh runs on the seat's bus alone (novox/hq ADR 0131, design 28 task 5.5). The old
transport's consume loop, build request, tool ask, management API and account scoping are
deleted, and the bus switch with them; the controller connects to the broker seat and to
nothing else. The store-window tests keep their assertions on a bus-less fake, and the tests
that only made sense for the old transport's in-memory holding go with it.

internal/link/bus_nats.go

@@ -1,66 +1,16 @@
 package link
 
 import (
-	"context"
-	"fmt"
-	"time"
-
-	"github.com/nats-io/nats.go"
-
 	"github.com/novox/mesh-controller/internal/broker"
 )
 
-// OverNats is the controller's outbound on the bus being built: the same three acts the other
-// transport has, on the subjects the permissions were derived for (design 25). A declaration is a
-// JetStream publish into NODES, where the node's own consumer waits for it; an event is announced on
-// the subject its name derives to; a tool is asked by request and reply on the module's tool subject.
-type OverNats struct{ JS *broker.JetStream }
-
-// declareSubject is where one node's declaration lands — the NODES stream's subject for it, and the
-// only subject that node's consumer delivers. The host subscribes exactly this.
-func declareSubject(node string) string { return "mesh.node." + node + ".declare" }
-
-func (b OverNats) PublishDeclaration(ctx context.Context, node string, body []byte) error {
-	publish, cancel := context.WithTimeout(ctx, 15*time.Second)
-	defer cancel()
-	if _, err := b.JS.Context().Publish(declareSubject(node), body, nats.Context(publish)); err != nil {
-		return fmt.Errorf("declaring to %s: %w", node, err)
-	}
-	return nil
-}
-
-func (b OverNats) PublishEvent(ctx context.Context, key, source, node string, body []byte) error {
-	// The key is the subject: the controller's own events are named in full, and what a module
-	// emits is derived before it reaches here. Headers carry the envelope the other transport put
-	// in message properties (ADR 0042), so a consumer reads who and when without the payload.
-	msg := nats.NewMsg(key)
-	msg.Data = body
-	msg.Header.Set("x-source", source)
-	msg.Header.Set("x-node", node)
-	msg.Header.Set("x-time", time.Now().UTC().Format(time.RFC3339Nano))
-	if err := b.JS.Conn().PublishMsg(msg); err != nil {
-		return fmt.Errorf("announcing %s: %w", key, err)
-	}
-	return nil
-}
-
-func (b OverNats) AskTool(ctx context.Context, module, tool string, args []byte, timeout time.Duration) ([]byte, error) {
-	ask, cancel := context.WithTimeout(ctx, timeout)
-	defer cancel()
-	reply, err := b.JS.Conn().RequestWithContext(ask, "mesh.mod."+module+".tool."+tool, args)
-	if err != nil {
-		return nil, fmt.Errorf("asking %s.%s: %w", module, tool, err)
-	}
-	return reply.Data, nil
-}
-
 // ConnectNats is Connect for the bus being built: the controller's inbound and outbound over one
 // JetStream connection the caller has already raised the streams on. Nothing is declared here —
 // the streams and the controller's consumers are asserted by Raise, before anything is served.
 func ConnectNats(js *broker.JetStream, enroller Enroller, listener Listener) *Server {
 	return &Server{
 		inbound:  Nats(js),
-		bus:      OverNats{JS: js},
+		bus:      OverNATS{JS: js.Context(), Conn: js.Conn()},
 		js:       js,
 		enroller: enroller,
 		listener: listener,