feat(server): present Silo identity and close the inherited upstream services

Two coupled changes that must land together, because the same files carry both:
the server now identifies itself as Silo, and every path that would have called
home to a MinIO-operated service is closed.

Product identity
- build-constants.go: store name, UA name and startup banner become Silo. The
  Go identifiers (MinioStoreName, MinioBannerName, ...) keep their names on
  purpose - renaming exported symbols would churn the compatibility surface for
  a cosmetic gain, and the rebrand guard freezes that surface.
- main.go, server-startup-msg.go, ftp-server.go and the user-visible log, help
  and error strings across cmd/ and internal/ switch to Silo. Original MinIO
  copyright, LICENSE, NOTICE and CREDITS are untouched; --version now prints
  the upstream copyright, the pgsty modification notice, and the trademark
  policy's approved "based on MinIO technology" attribution.
- api-headers.go: the HTTP Server header becomes "Silo". This is the one
  externally observable identity change, so TestCommonHeadersUseSiloProductName
  pins it - probes that sniff for "MinIO" must move to capability detection.
- Prometheus metric HELP strings keep their MinIO wording. They are part of the
  metrics contract the guard protects, not product copy.

Configuration directory
- config-dir.go: new installs use ~/.silo. If only ~/.minio exists it is still
  read, with a one-time notice and no files moved. If both exist ~/.silo wins
  and an ambiguity warning is emitted; an explicit --config-dir always wins.
  Covered by TestSelectDefaultConfigDir. The internal .minio.sys layout is
  never renamed - this rule applies to the user config directory only.

Upstream service lockdown
- globalInplaceUpdateDisabled is now true at initialization rather than being
  set from MINIO_UPDATE. common-main.go still parses MINIO_UPDATE so upgrading
  nodes do not fail on an unknown key, but warns that the value is ignored;
  there is no way to re-enable the updater. TestInplaceUpdateCannotBeEnabled
  guards that. Without this, an admin with mc could have overwritten
  /usr/bin/silo with an upstream MinIO binary.
- verifyBinary and commitBinary refuse early; the ServerUpdate v1/v2 admin
  routes and the peer-rest update endpoints stay registered and keep returning
  the existing programmatic error, so clients see a stable failure rather than
  a 404.
- MinioReleaseBaseURL and defaultMinisignPubkey are emptied: no dl.min.io
  download root, and upstream's minisign key is no longer a trust root for
  anything this fork ships.
- cmd/callhome.go is deleted and internal/config/subnet/ is reduced to parsing
  its old keys and reporting that the integration is disabled. config-current.go
  warns instead of failing when callhome or SUBNET settings are present, so an
  upgraded node with those keys still starts.
- internal/config/errors.go replaces the MinIO Slack and support entry points
  with Silo documentation and issue links. Error codes and programmatic fields
  are unchanged.

Verified: the compatibility baseline is unchanged except for the deliberate
removal of the /api/health/upload SUBNET route; go build, go vet and the full
cmd/ and internal/ unit suites pass; a locally built binary starts, serves
S3/Admin/metrics on the unchanged /minio/* routes, answers with Server: Silo,
and falls back to a pre-existing ~/.minio with the expected notice.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

cmd/server-main.go

@@ -114,7 +114,7 @@ var ServerFlags = []cli.Flag{
 	},
 	cli.StringFlag{
 		Name:   "interface",
-		Usage:  "bind to right VRF device for MinIO services",
+		Usage:  "bind to the VRF device used by Silo services",
 		Hidden: true,
 		EnvVar: "MINIO_INTERFACE",
 	},
@@ -220,20 +220,20 @@ FLAGS:
   {{range .VisibleFlags}}{{.}}
   {{end}}{{end}}
 EXAMPLES:
-  1. Start MinIO server on "/home/shared" directory.
+  1. Start Silo server on "/home/shared" directory.
      {{.Prompt}} {{.HelpName}} /home/shared
 
   2. Start single node server with 64 local drives "/mnt/data1" to "/mnt/data64".
      {{.Prompt}} {{.HelpName}} /mnt/data{1...64}
 
-  3. Start distributed MinIO server on an 32 node setup with 32 drives each, run following command on all the nodes
+  3. Start distributed Silo server on a 32-node setup with 32 drives each; run the following command on all nodes.
      {{.Prompt}} {{.HelpName}} http://node{1...32}.example.com/mnt/export{1...32}
 
-  4. Start distributed MinIO server in an expanded setup, run the following command on all the nodes
+  4. Start distributed Silo server in an expanded setup; run the following command on all nodes.
      {{.Prompt}} {{.HelpName}} http://node{1...16}.example.com/mnt/export{1...32} \
             http://node{17...64}.example.com/mnt/export{1...64}
 
-  5. Start distributed MinIO server, with FTP and SFTP servers on all interfaces via port 8021, 8022 respectively
+  5. Start distributed Silo server with FTP and SFTP on ports 8021 and 8022.
      {{.Prompt}} {{.HelpName}} http://node{1...4}.example.com/mnt/export{1...4} \
            --ftp="address=:8021" --ftp="passive-port-range=30000-40000" \
            --sftp="address=:8022" --sftp="ssh-private-key=${HOME}/.ssh/id_rsa"
@@ -597,7 +597,7 @@ func initServerConfig(ctx context.Context, newObject ObjectLayer) error {
 
 		// These messages only meant primarily for distributed setup, so only log during distributed setup.
 		if globalIsDistErasure {
-			logger.Info("Waiting for all MinIO sub-systems to be initialize...")
+			logger.Info("Waiting for all Silo subsystems to initialize...")
 		}
 
 		// Upon success migrating the config, initialize all sub-systems
@@ -607,13 +607,13 @@ func initServerConfig(ctx context.Context, newObject ObjectLayer) error {
 			// All successful return.
 			if globalIsDistErasure {
 				// These messages only meant primarily for distributed setup, so only log during distributed setup.
-				logger.Info("All MinIO sub-systems initialized successfully in %s", time.Since(t1))
+				logger.Info("All Silo subsystems initialized successfully in %s", time.Since(t1))
 			}
 			return nil
 		}
 
 		if configRetriableErrors(err) {
-			logger.Info("Waiting for all MinIO sub-systems to be initialized.. possible cause (%v)", err)
+			logger.Info("Waiting for all Silo subsystems to initialize; possible cause: %v", err)
 			time.Sleep(time.Duration(r.Float64() * float64(5*time.Second)))
 			continue
 		}
@@ -742,7 +742,7 @@ func initializeLogRotate(ctx *cli.Context) (io.WriteCloser, error) {
 	return output, nil
 }
 
-// serverMain handler called for 'minio server' command.
+// serverMain handles the 'silo server' command.
 func serverMain(ctx *cli.Context) {
 	r := rand.New(rand.NewSource(time.Now().UnixNano()))
 
@@ -851,16 +851,6 @@ func serverMain(ctx *cli.Context) {
 		getCert = globalTLSCerts.GetCertificate
 	}
 
-	// Check for updates in non-blocking manner.
-	go func() {
-		if !globalServerCtxt.Quiet && !globalInplaceUpdateDisabled {
-			// Check for new updates from dl.min.io.
-			bootstrapTrace("checkUpdate", func() {
-				checkUpdate(getMinioMode())
-			})
-		}
-	}()
-
 	// Set system resources to maximum.
 	bootstrapTrace("setMaxResources", func() {
 		_ = setMaxResources(globalServerCtxt)
@@ -868,13 +858,13 @@ func serverMain(ctx *cli.Context) {
 
 	// Verify kernel release and version.
 	if oldLinux() {
-		warnings = append(warnings, color.YellowBold("Detected Linux kernel version older than 4.0 release, there are some known potential performance problems with this kernel version. MinIO recommends a minimum of 4.x linux kernel version for best performance"))
+		warnings = append(warnings, color.YellowBold("Detected a Linux kernel older than 4.0; Silo recommends kernel 4.x or newer to avoid known performance problems"))
 	}
 
 	maxProcs := runtime.GOMAXPROCS(0)
 	cpuProcs := runtime.NumCPU()
 	if maxProcs < cpuProcs {
-		warnings = append(warnings, color.YellowBold("Detected GOMAXPROCS(%d) < NumCPU(%d), please make sure to provide all PROCS to MinIO for optimal performance",
+		warnings = append(warnings, color.YellowBold("Detected GOMAXPROCS(%d) < NumCPU(%d); provide all processors to Silo for optimal performance",
 			maxProcs, cpuProcs))
 	}
 
@@ -1161,7 +1151,7 @@ func serverMain(ctx *cli.Context) {
 			Transport: globalRemoteTargetTransport,
 			Region:    region,
 		})
-		logger.FatalIf(err, "Unable to initialize MinIO client")
+		logger.FatalIf(err, "Unable to initialize the internal S3 client")
 	})
 
 	go bootstrapTrace("startResourceMetricsCollection", func() {
@@ -1169,7 +1159,7 @@ func serverMain(ctx *cli.Context) {
 	})
 
 	// Add User-Agent to differentiate the requests.
-	globalMinioClient.SetAppInfo("minio-perf-test", ReleaseTag)
+	globalMinioClient.SetAppInfo("silo-perf-test", ReleaseTag)
 
 	if serverDebugLog {
 		fmt.Println("== DEBUG Mode enabled ==")