Revert #9443 — heartbeat peer binding breaks hostname-based clusters (#9474)

Revert "master: bind heartbeat claims to the connecting peer (#9443)"

This reverts commit f28c7ce6df.

The strict heartbeat-ip-vs-peer match in authorizeHeartbeatPeer rejects
every hostname-based deployment. In docker-compose / k8s the volume
server is started with -ip=<service-name> and the gRPC peer surfaces
as the container/pod IP, so the two never match and every heartbeat
fails with `heartbeat ip "volume" does not match peer "172.18.0.3"`.
The master therefore never learns about any volume, growth fails, and
fio writes against the mount return EIO.

After the #9440 revert merged (43a8c4fdc), the e2e workflow is still
failing for this reason; see
https://github.com/seaweedfs/seaweedfs/actions/runs/25767265775 .

Reverting to unblock e2e. A narrower re-do should accept the heartbeat
when heartbeat.Ip resolves (DNS) to the peer address, so the spoof
hardening can return without breaking hostname-based clusters.

weed/command/master.go

@@ -74,10 +74,6 @@ type MasterOptions struct {
 	telemetryEnabled   *bool
 	debug              *bool
 	debugPort          *int
-	// allowUntrustedHeartbeat disables the source-ip binding check on
-	// SendHeartbeat. Required for deployments where a NAT or proxy sits
-	// between volume servers and the master.
-	allowUntrustedHeartbeat *bool
 	// shutdownCtx, when non-nil, tells startMaster to shut down once the ctx
 	// is cancelled. Used by integration tests and by weed mini; nil for
 	// standalone weed master.
@@ -113,7 +109,6 @@ func init() {
 	m.telemetryEnabled = cmdMaster.Flag.Bool("telemetry", false, "enable telemetry reporting")
 	m.debug = cmdMaster.Flag.Bool("debug", false, "serves runtime profiling data via pprof on the port specified by -debug.port")
 	m.debugPort = cmdMaster.Flag.Int("debug.port", 6060, "http port for debugging")
-	m.allowUntrustedHeartbeat = cmdMaster.Flag.Bool("master.allowUntrustedHeartbeat", false, "accept volume server heartbeats whose advertised ip does not match the gRPC peer address (required behind NAT/proxy)")
 }
 
 var cmdMaster = &Command{
@@ -468,6 +463,5 @@ func (m *MasterOptions) toMasterOption(whiteList []string) *weed_server.MasterOp
 		MetricsIntervalSec:      *m.metricsIntervalSec,
 		TelemetryUrl:            *m.telemetryUrl,
 		TelemetryEnabled:        *m.telemetryEnabled,
-		AllowUntrustedHeartbeat: m.allowUntrustedHeartbeat != nil && *m.allowUntrustedHeartbeat,
 	}
 }