feat(backend,helm)!: bind to IPv6 wildcard by default for dual-stack support

* fix: Enable Garage UI to work on IPv6-based clusters.

* fix: building on nonstandard-uid machines.

* fix: Enable Garage UI to work on IPv6-based clusters.

backend/internal/config/config.go

@@ -2,7 +2,9 @@ package config
 
 import (
 	"fmt"
+	"net"
 	"os"
+	"strconv"
 	"strings"
 
 	"github.com/spf13/viper"
@@ -160,7 +162,7 @@ func Load(configPath string, opts ...LoadOption) (*Config, error) {
 	viper.SetConfigType("yaml")
 
 	// Built-in defaults (lowest priority)
-	viper.SetDefault("server.host", "0.0.0.0")
+	viper.SetDefault("server.host", "::")
 	viper.SetDefault("server.port", 8080)
 	viper.SetDefault("server.environment", "production")
 	viper.SetDefault("garage.force_path_style", true)
@@ -383,7 +385,7 @@ func (c *Config) Validate() error {
 
 // GetAddress returns the full server address (host:port)
 func (c *Config) GetAddress() string {
-	return fmt.Sprintf("%s:%d", c.Server.Host, c.Server.Port)
+	return net.JoinHostPort(c.Server.Host, strconv.Itoa(c.Server.Port))
 }
 
 // IsDevelopment returns true if running in development mode

backend/internal/config/config_test.go

@@ -83,6 +83,9 @@ func TestLoad_EnvOnly_MissingFile(t *testing.T) {
 	if cfg.Server.Port != 9090 {
 		t.Errorf("Server.Port = %d, want 9090 (from env)", cfg.Server.Port)
 	}
+	if cfg.Server.Host != "::" {
+		t.Errorf("Server.Host = %q, want :: (default)", cfg.Server.Host)
+	}
 	if cfg.Garage.AdminToken != "env-token" {
 		t.Errorf("Garage.AdminToken = %q, want env-token", cfg.Garage.AdminToken)
 	}
@@ -367,6 +370,8 @@ func TestGetAddress(t *testing.T) {
 	}{
 		{"localhost", 8080, "localhost:8080"},
 		{"0.0.0.0", 80, "0.0.0.0:80"},
+		{"::", 80, "[::]:80"},
+		{"::1", 443, "[::1]:443"},
 		{"", 443, ":443"},
 	}
 	for _, tc := range tests {