fix: address final review findings (clip reset, codecs, paths, timeline)

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

src-tauri/src/commands/export.rs

@@ -25,6 +25,7 @@ pub async fn export_clips(
     on_event: Channel<ExportEvent>,
 ) -> Result<Vec<String>, String> {
     tokio::task::spawn_blocking(move || {
+        let output_directory = clip_exporter::expand_tilde_path(&config.output_directory);
         let ext = clip_exporter::get_extension(&config.source_file_path, &config.cut_mode);
 
         match config.export_scope {
@@ -40,7 +41,7 @@ pub async fn export_clips(
                     });
 
                     let output = clip_exporter::generate_output_path(
-                        &config.output_directory,
+                        &output_directory,
                         &config.video_title,
                         &clip.label,
                         &ext,
@@ -69,7 +70,7 @@ pub async fn export_clips(
                 });
 
                 let output = clip_exporter::generate_output_path(
-                    &config.output_directory,
+                    &output_directory,
                     &config.video_title,
                     "Merged",
                     &ext,