feat: field-sync-gui MVP — Wails GUI ingest SD→local+S3 (4 slots //)

internal/config/config.go

@@ -0,0 +1,42 @@
+package config
+
+import (
+	"os"
+	"strconv"
+
+	"github.com/joho/godotenv"
+)
+
+// Config holds runtime configuration
+type Config struct {
+	S3Bucket    string `json:"s3Bucket"`
+	LocalDest   string `json:"localDest"`
+	AWSProfile  string `json:"awsProfile"`
+	Concurrency int    `json:"concurrency"`
+}
+
+// Load reads config from ENV (with optional .env file)
+func Load(envFile string) Config {
+	_ = godotenv.Load(envFile) // ignore if missing
+
+	concurrency := 4
+	if v := os.Getenv("FIELD_SYNC_CONCURRENCY"); v != "" {
+		if n, err := strconv.Atoi(v); err == nil && n > 0 {
+			concurrency = n
+		}
+	}
+
+	return Config{
+		S3Bucket:    getenv("FIELD_SYNC_S3_BUCKET", ""),
+		LocalDest:   getenv("FIELD_SYNC_LOCAL_DEST", os.TempDir()),
+		AWSProfile:  getenv("AWS_PROFILE", "cosma"),
+		Concurrency: concurrency,
+	}
+}
+
+func getenv(key, fallback string) string {
+	if v := os.Getenv(key); v != "" {
+		return v
+	}
+	return fallback
+}