Fix Dokploy Bad Gateway: drop required .env and add app healthcheck.

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/config/config.go

@@ -25,8 +25,14 @@ type Config struct {
 func Load() (*Config, error) {
 	_ = godotenv.Load()
 
+	// Dokploy / PaaS often set PORT; prefer APP_PORT, then PORT.
+	port := getEnv("APP_PORT", "")
+	if port == "" {
+		port = getEnv("PORT", "8080")
+	}
+
 	cfg := &Config{
-		Port:          getEnv("APP_PORT", "8080"),
+		Port:          port,
 		Secret:        getEnv("APP_SECRET", "dev-secret-change-me"),
 		Env:           getEnv("APP_ENV", "development"),
 		DatabaseURL:   os.Getenv("DATABASE_URL"),