feat(inbound): excludeFromSub hides links without disabling (#6463)

* feat(inbound): excludeFromSub hides links without disabling

Add a per-inbound flag that omits subscription output while keeping the
inbound enabled for Xray, auth, and traffic accounting. Fixes #6435.

* fix(inbound): excludeFromSub review follow-ups

gofumpt model.go, sync docs OpenAPI, keep excludeFromSub master-authored
on node mirror, and exercise the legacy add-column migration path in tests.

* fix(sub): keep excluded inbounds' clients in the usage header

The excludeFromSub filter sat in getInboundsBySubId's SQL, so an excluded
inbound's clients never reached seenEmails in the raw, Clash or JSON
renderer. A client that lives only on a hidden inbound (one client per
inbound sharing a subId) dropped out of the Subscription-Userinfo usage,
quota and expiry and out of the info-node state, while the inbound kept
serving it and counting its traffic.

The query returns every enabled inbound again; each renderer skips an
excluded inbound's links but still counts its clients, the same rule the
Clash renderer already applies to external links it cannot express.

---------

Co-authored-by: mrchatam <mrchatam@users.noreply.github.com>
Co-authored-by: MHSanaei <ho3ein.sanaei@gmail.com>

internal/sub/service.go

@@ -330,6 +330,18 @@ func (s *SubService) matchingClients(inbound *model.Inbound, subId string) []mod
 	return out
 }
 
+// countHiddenClients adds an excludeFromSub inbound's clients to the usage set:
+// the inbound still serves them, so only its links leave the subscription.
+func countHiddenClients(clients []model.Client, seenEmails map[string]struct{}) (anyEnabled bool) {
+	for _, client := range clients {
+		seenEmails[client.Email] = struct{}{}
+		if client.Enable {
+			anyEnabled = true
+		}
+	}
+	return anyEnabled
+}
+
 // overlayInboundTunnelIdentity copies per-inbound tunnel fields from settings.
 // An unmatched peer is dropped, malformed settings yield nothing, and empty optional secrets replace shared values (#6641).
 func (s *SubService) overlayInboundTunnelIdentity(inbound *model.Inbound, clients []model.Client) ([]model.Client, error) {
@@ -473,6 +485,12 @@ func (s *SubService) getSubs(subId string) ([]string, []string, int64, xray.Clie
 		if len(clients) == 0 {
 			continue
 		}
+		if inbound.ExcludeFromSub {
+			if countHiddenClients(clients, seenEmails) {
+				hasEnabledClient = true
+			}
+			continue
+		}
 		s.projectThroughFallbackMaster(inbound)
 		// Host overrides apply AFTER fallback projection so a host's
 		// address/TLS wins over the projected master stream.