fix: crash on dump file with empty path (closed #78)

Author: gustavo-munhoz

src/main.rs

@@ -83,7 +83,9 @@ fn main() -> Result<()> {
 
     runner.run().context("runner failed")?;
 
-    if let Some(path) = dump_path {
+    if let Some(path) = dump_path
+        && !path.as_os_str().is_empty()
+    {
         runner
             .curve()
             .export(&path, CurveFormat::from(dump_format))

src/ui/cli/wizard/wizard.rs

@@ -149,9 +149,6 @@ pub fn prompt_choice<C: UIChoice, D: PromptDriver>(driver: &D) -> Result<C> {
 
                         if let Some(idx) = none_idx {
                             if selected == "— none —" && start_idx == idx {
-                                // treat "none" as absence; skip insert by returning None
-                                // (the outer `if let Some(val)` will just not insert)
-                                // If you prefer explicit null, return Some(Value::Null) here.
                                 None
                             } else if selected == "— none —" {
                                 None