feat(media-supply): resource cache sync and order flow refinements

Add a resource cache sync entrypoint (RunMediaResourceSyncOnce) driven
by the new scheduler job, and rework the backlink/sync worker around it.
Tune the meijiequan client and slow the default backlink sync interval
from 10m to 30m to reduce upstream pressure.

Trim unused public/transport surface (handler + router + swagger) and
simplify admin-web order management and ops-web media-supply views,
dropping stale shared-types fields.

server/internal/shared/config/config.go

@@ -844,7 +844,7 @@ func NormalizeMediaSupplyConfig(cfg *MediaSupplyConfig) {
 		cfg.Worker.SyncMaxAttempts = 2
 	}
 	if cfg.Worker.BacklinkSyncInterval <= 0 {
-		cfg.Worker.BacklinkSyncInterval = 10 * time.Minute
+		cfg.Worker.BacklinkSyncInterval = 30 * time.Minute
 	}
 	if cfg.Worker.BacklinkBatchSize <= 0 {
 		cfg.Worker.BacklinkBatchSize = 20