feat(auth): add MINDA_DEMO support with auto-seeded demo accounts and username login

internal/config/config.go

@@ -14,6 +14,7 @@ type Config struct {
 	BaseURL           string
 	AllowRegistration bool
 	LogLevel          string
+	DemoMode          bool
 
 	// Optional SMTP environment variables (can also be overridden/configured in DB system_settings)
 	SMTPHost string
@@ -41,6 +42,9 @@ func Load() *Config {
 	allowReg := strings.ToLower(getEnv("ALLOW_REGISTRATION", "false")) == "true"
 	logLevel := getEnv("LOG_LEVEL", "info")
 
+	demoVal := strings.ToLower(getEnv("MINDA_DEMO", getEnv("MINDSIFT_DEMO", getEnv("DEMO_MODE", "false"))))
+	demoMode := demoVal == "true" || demoVal == "1" || demoVal == "yes" || demoVal == "on"
+
 	smtpHost := getEnv("SMTP_HOST", "")
 	smtpPort := getEnv("SMTP_PORT", "587")
 	smtpUser := getEnv("SMTP_USER", "")
@@ -56,6 +60,7 @@ func Load() *Config {
 		BaseURL:           baseURL,
 		AllowRegistration: allowReg,
 		LogLevel:          logLevel,
+		DemoMode:          demoMode,
 		SMTPHost:          smtpHost,
 		SMTPPort:          smtpPort,
 		SMTPUser:          smtpUser,