Render Queue: clicking the Output To file name opens a save dialog (#192)

Clicking an item's Output To file name opened an inline editor on the
name template (`[compName].[fileExtension]`), so there was no way to
pick a folder from there. Choose File… in the menu beside it did open
a dialog, but the project save dialog: filtered to .ecproj and opening
wherever the OS chose.

As After Effects' Output Movie To, clicking the file name now opens a
save dialog at the current output (its folder and name) for the output
format's extension, and the chosen file becomes the output. Choose
File… opens the same dialog. Alt-click still edits the template in
place, and hosts without a save dialog (the web) keep the inline
editor. The desktop `pick_save_file` hook opens in the folder of a
default path.

Test: clicking_the_output_file_name_opens_the_save_dialog.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/effectcraft/src/main.rs

@@ -145,7 +145,14 @@ fn main() -> eframe::Result {
             app.hooks.audio_devices = Some(Box::new(audio_out::devices));
             app.hooks.pick_folder = Some(Box::new(|| rfd::FileDialog::new().pick_folder().map(|p| p.to_string_lossy().to_string())));
             app.hooks.pick_save_file = Some(Box::new(|name: &str, ext: &str| {
-                rfd::FileDialog::new().add_filter(ext, &[ext]).set_file_name(name).save_file().map(|p| p.to_string_lossy().to_string())
+                // A default with a folder that exists opens the dialog there.
+                let path = std::path::Path::new(name);
+                let mut d = rfd::FileDialog::new().add_filter(ext, &[ext]);
+                if let Some(dir) = path.parent().filter(|d| d.is_dir()) {
+                    d = d.set_directory(dir);
+                }
+                let file = path.file_name().map(|n| n.to_string_lossy().to_string()).unwrap_or_default();
+                d.set_file_name(file).save_file().map(|p| p.to_string_lossy().to_string())
             }));
             #[cfg(target_os = "macos")]
             {