feat(desktop): push publish tasks via AMQP topic dispatch WebSocket

Introduce a desktop.task.dispatch topic exchange with per-client routing
keys. Tenant-api publishes a task_available frame keyed by target client
ID when a publish job is created; every instance binds its own transient
queue and forwards to the matching WebSocket (/api/desktop/dispatch) it
owns. Desktop-client now prefers this push channel and only falls back
to HTTP /lease polling when the socket is down. Also drop admin-web
monitoring-plugin remnants and scope the publish modal account list to
publish platforms.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/internal/bootstrap/bootstrap.go

@@ -45,8 +45,9 @@ type App struct {
 	VectorStore       retrieval.VectorStore
 	ObjectStorage     objectstorage.Client
 	AuditLogs         *auditlog.AsyncWriter
-	GenerationStreams *stream.GenerationHub
+	GenerationStreams  *stream.GenerationHub
 	DesktopTaskStreams *stream.DesktopTaskHub
+	DesktopDispatch    *stream.DesktopDispatchHub
 	Cache             cache.Cache
 	KolProfiles       repository.KolProfileRepository
 	KolPackages       repository.KolPackageRepository
@@ -111,6 +112,10 @@ func New(configPath string) (*App, error) {
 	auditLogs := auditlog.NewAsyncWriter(pool, logger)
 	generationStreams := stream.NewGenerationHub(mqClient)
 	desktopTaskStreams := stream.NewDesktopTaskHub(mqClient)
+	desktopDispatchBindings := []string{
+		cfg.RabbitMQ.DesktopDispatchPublishPrefix + ".*",
+	}
+	desktopDispatch := stream.NewDesktopDispatchHub(mqClient, logger, desktopDispatchBindings)
 	appCache := cache.New(cfg.Cache.Driver, rdb)
 	kolProfiles := repository.NewKolProfileRepository(pool)
 	kolPackages := repository.NewKolPackageRepository(pool)
@@ -170,8 +175,9 @@ func New(configPath string) (*App, error) {
 		VectorStore:       vectorStore,
 		ObjectStorage:     objectStorageClient,
 		AuditLogs:         auditLogs,
-		GenerationStreams: generationStreams,
+		GenerationStreams:  generationStreams,
 		DesktopTaskStreams: desktopTaskStreams,
+		DesktopDispatch:    desktopDispatch,
 		Cache:             appCache,
 		KolProfiles:       kolProfiles,
 		KolPackages:       kolPackages,