fix: cross-platform compatibility for Windows support

- Use directories::BaseDirs for config path fallback instead of hardcoded Unix path
- Default to notepad on Windows instead of vi for editor commands
- Skip +N line argument for notepad in todo edit (notepad doesn't support it)

src/config.rs

@@ -37,8 +37,10 @@ impl Settings {
     fn config_path() -> PathBuf {
         if let Some(proj_dirs) = ProjectDirs::from("", "", "streamd") {
             proj_dirs.config_dir().join("config.toml")
+        } else if let Some(base_dirs) = directories::BaseDirs::new() {
+            base_dirs.config_dir().join("streamd").join("config.toml")
         } else {
-            PathBuf::from("~/.config/streamd/config.toml")
+            PathBuf::from("streamd_config.toml")
         }
     }
 }