Elect one fleet torrent seeder per AWS VPC via IMDS cloud_instance_meta.

Agents read vpc-id from EC2 IMDS on auth; the server scopes subnet_primary_seeder to vpc-id with /24 fallback, exposes VPC seeder badges, and documents cross-VPC gossip via peering/TGW.

server/internal/erasure/lanes.go

@@ -14,10 +14,9 @@ var parallelLaneOrder = []string{
 
 // ShardRef is one erasure shard served on a parallel lane URL.
 type ShardRef struct {
-	Index   int    `json:"index"`
-	Lane    string `json:"lane"`
-	URL     string `json:"url"`
-	EdgeURL string `json:"edge_url,omitempty"`
+	Index int    `json:"index"`
+	Lane  string `json:"lane"`
+	URL   string `json:"url"`
 }
 
 // Plan is deploy-plan metadata for agent-side Reed–Solomon reassembly.