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/go.mod

@@ -1,6 +1,6 @@
 module github.com/geo-platform/tenant-api
 
-go 1.22.2
+go 1.23
 
 require (
 	github.com/alicebob/miniredis/v2 v2.37.0
@@ -10,6 +10,7 @@ require (
 	github.com/gin-gonic/gin v1.9.1
 	github.com/golang-jwt/jwt/v5 v5.2.1
 	github.com/google/uuid v1.6.0
+	github.com/gorilla/websocket v1.5.3
 	github.com/jackc/pgx/v5 v5.5.5
 	github.com/ledongthuc/pdf v0.0.0-20240314090751-a2a84ec735c3
 	github.com/minio/minio-go/v7 v7.0.83