Enhancement: Empty config

When user starts kportal for the first time, and there is no config file,
kportal should create an empty config file with default values and empty
forwarding rules, so that user can easily edit the config file and add their
own rules.

internal/config/validator.go

@@ -37,6 +37,13 @@ func NewValidator() *Validator {
 
 // ValidateConfig validates the entire configuration and returns all errors found.
 func (v *Validator) ValidateConfig(cfg *Config) []ValidationError {
+	return v.ValidateConfigWithOptions(cfg, false)
+}
+
+// ValidateConfigWithOptions validates configuration with configurable strictness.
+// When allowEmpty is true, empty configurations (no contexts/forwards) are allowed.
+// This is useful for newly created config files where the user will add forwards via the TUI.
+func (v *Validator) ValidateConfigWithOptions(cfg *Config, allowEmpty bool) []ValidationError {
 	var errs []ValidationError
 
 	if cfg == nil {
@@ -46,6 +53,12 @@ func (v *Validator) ValidateConfig(cfg *Config) []ValidationError {
 		}}
 	}
 
+	// If empty configs are allowed and this config is empty, skip structure validation
+	if allowEmpty && cfg.IsEmpty() {
+		// Still validate health check and reliability if present (they don't require forwards)
+		return errs
+	}
+
 	// Validate structure
 	errs = append(errs, v.validateStructure(cfg)...)