Fix what the Go 1.26 language bump breaks (#10794)

* worker: log the balance move stage through a constant format string

Go 1.26's printf analyzer now follows printf wrappers reached through an
interface, so passing the stage straight to Logger.Info is a vet failure.

* s3api: bracket the IPv6 host in the signature test URL

A bare IPv6 literal is legal in a Host header but never in a URL. Go 1.26
stopped parsing it leniently, so carry the two forms separately and set
r.Host to the value the client would actually have signed.

* mini: bracket IPv6 addresses in the readiness probe URLs

An IPv6-only host hands mini a bare literal, and %s:%d pasted it into a URL
unbracketed. Under Go 1.26 that URL no longer parses, so waiting for the
admin server never succeeds and mini refuses to start.

weed/command/mini.go

@@ -1473,7 +1473,7 @@ func startMiniService(name string, fn func(), port int) {
 // waitForServiceReady pings the service HTTP endpoint to check if it's ready
 // to accept connections, and reports the transition to the progress board.
 func waitForServiceReady(name string, port int, bindIp string) {
-	address := fmt.Sprintf("http://%s:%d", bindIp, port)
+	address := "http://" + util.JoinHostPort(bindIp, port)
 	healthAddr := getHealthCheckAddr(address)
 	maxAttempts := 30 // 30 * 200ms = 6 seconds max wait
 	attempt := 0
@@ -1595,7 +1595,7 @@ func startMiniAdminWithWorker(allServicesReady chan struct{}) {
 	}()
 
 	// Wait for admin server's HTTP port to be ready before launching worker
-	adminAddr := fmt.Sprintf("http://%s:%d", bindIp, *miniAdminOptions.port)
+	adminAddr := "http://" + util.JoinHostPort(bindIp, *miniAdminOptions.port)
 	if err := waitForAdminServerReady(ctx, adminAddr); err != nil {
 		// If the parent context was cancelled (e.g. a previous in-process
 		// mini run is being torn down), bail out gracefully instead of
@@ -1900,7 +1900,7 @@ func printWelcomeMessage() {
 // Best-effort: any error returns ok=false so the welcome banner simply omits
 // the lines.
 func miniVolumeCounts() (max, free int64, ok bool) {
-	url := getHealthCheckAddr(fmt.Sprintf("http://%s:%d/dir/status", *miniIp, *miniMasterOptions.port))
+	url := getHealthCheckAddr("http://" + util.JoinHostPort(*miniIp, *miniMasterOptions.port) + "/dir/status")
 	client := &http.Client{Timeout: 2 * time.Second}
 	resp, err := client.Get(url)
 	if err != nil {