chore: add go config and logging layer

platform/config/config.go

@@ -0,0 +1,87 @@
+package config
+
+import (
+	"fmt"
+	"log/slog"
+	"os"
+	"strconv"
+	"strings"
+)
+
+type Config struct {
+	AppEnv             string
+	LogLevel           slog.Level
+	BackendAddr        string
+	ConsoleProxyAddr   string
+	WorkerConcurrency int
+	DatabaseURL        string
+	DatabaseDirectURL  string
+	SupabaseURL        string
+	SupabaseJWKSURL    string
+	SupabaseIssuer     string
+	RedisAddr          string
+}
+
+func Load() (Config, error) {
+	logLevel, err := parseLogLevel(getenv("LOG_LEVEL", "info"))
+	if err != nil {
+		return Config{}, err
+	}
+
+	workerConcurrency, err := intFromEnv("WORKER_CONCURRENCY", 5)
+	if err != nil {
+		return Config{}, err
+	}
+	if workerConcurrency < 1 {
+		return Config{}, fmt.Errorf("WORKER_CONCURRENCY must be greater than 0")
+	}
+
+	return Config{
+		AppEnv:             getenv("APP_ENV", "development"),
+		LogLevel:           logLevel,
+		BackendAddr:        getenv("BACKEND_ADDR", ":8080"),
+		ConsoleProxyAddr:   getenv("CONSOLE_PROXY_ADDR", ":8081"),
+		WorkerConcurrency: workerConcurrency,
+		DatabaseURL:        os.Getenv("DATABASE_URL"),
+		DatabaseDirectURL:  os.Getenv("DATABASE_DIRECT_URL"),
+		SupabaseURL:        os.Getenv("SUPABASE_URL"),
+		SupabaseJWKSURL:    os.Getenv("SUPABASE_JWKS_URL"),
+		SupabaseIssuer:     os.Getenv("SUPABASE_ISSUER"),
+		RedisAddr:          getenv("REDIS_ADDR", "localhost:6379"),
+	}, nil
+}
+
+func getenv(key, fallback string) string {
+	if value := strings.TrimSpace(os.Getenv(key)); value != "" {
+		return value
+	}
+	return fallback
+}
+
+func intFromEnv(key string, fallback int) (int, error) {
+	raw := strings.TrimSpace(os.Getenv(key))
+	if raw == "" {
+		return fallback, nil
+	}
+
+	value, err := strconv.Atoi(raw)
+	if err != nil {
+		return 0, fmt.Errorf("%s must be an integer: %w", key, err)
+	}
+	return value, nil
+}
+
+func parseLogLevel(raw string) (slog.Level, error) {
+	switch strings.ToLower(strings.TrimSpace(raw)) {
+	case "debug":
+		return slog.LevelDebug, nil
+	case "info":
+		return slog.LevelInfo, nil
+	case "warn", "warning":
+		return slog.LevelWarn, nil
+	case "error":
+		return slog.LevelError, nil
+	default:
+		return slog.LevelInfo, fmt.Errorf("LOG_LEVEL must be one of debug, info, warn, error")
+	}
+}