fix(node): import per-client traffic history on first sync of a node-hosted inbound

On the first sync of a node-hosted inbound, the central inbound adopted the
node's full lifetime counter but every client_traffics row was seeded at 0 (with
the delta baseline set to the node's current counter). So adding or migrating a
node that already had traffic kept the inbound total correct while every
per-client counter restarted from zero, and the master under-reported per-client
usage by the entire pre-attach history.

Seed a new client_traffics row from the node counter only when the inbound was
created during the same sync (a genuine node-add / inbound re-import); a client
reappearing under a pre-existing inbound still seeds 0, preserving the ghost
protection in TestGhostData_NoPhantomTraffic. The seed is additionally gated on
the delete tombstone so a just-deleted client cannot be resurrected if its
inbound is recreated. Baseline still equals the seeded value, so the next sync
delta is 0 and no traffic is double counted.

Adds TestNodeAdd_ImportsClientHistoryWithNewInbound and
TestNodeAdd_TombstonedClientNotResurrected.

internal/web/service/inbound_node.go

@@ -380,6 +380,8 @@ func (s *InboundService) setRemoteTrafficLocked(nodeID int, snap *runtime.Traffi
 
 	structuralChange := false
 
+	newInboundIDs := make(map[int]struct{})
+
 	snapTags := make(map[string]struct{}, len(snap.Inbounds))
 	for _, snapIb := range snap.Inbounds {
 		if snapIb == nil {
@@ -466,6 +468,7 @@ func (s *InboundService) setRemoteTrafficLocked(nodeID int, snap *runtime.Traffi
 			if newIb.Tag != snapIb.Tag {
 				tagToCentral[newIb.Tag] = &newIb
 			}
+			newInboundIDs[newIb.Id] = struct{}{}
 			structuralChange = true
 			continue
 		}
@@ -620,6 +623,10 @@ func (s *InboundService) setRemoteTrafficLocked(nodeID int, snap *runtime.Traffi
 				if dirty {
 					continue
 				}
+				var seedUp, seedDown int64
+				if _, isNewInbound := newInboundIDs[c.Id]; isNewInbound && !isClientEmailTombstoned(cs.Email) {
+					seedUp, seedDown = canon.Up, canon.Down
+				}
 				row := &xray.ClientTraffic{
 					InboundId:  c.Id,
 					Email:      cs.Email,
@@ -627,8 +634,8 @@ func (s *InboundService) setRemoteTrafficLocked(nodeID int, snap *runtime.Traffi
 					Total:      cs.Total,
 					ExpiryTime: cs.ExpiryTime,
 					Reset:      cs.Reset,
-					Up:         0,
-					Down:       0,
+					Up:         seedUp,
+					Down:       seedDown,
 					LastOnline: cs.LastOnline,
 				}
 				if err := tx.Clauses(clause.OnConflict{Columns: []clause.Column{{Name: "email"}}, DoNothing: true}).