fix: Allow file list panel to be resized beyond 460px

Changed width_range from 160.0..=460.0 to 160.0..=f32::INFINITY to allow
the user to make the file list panel as wide as they want without it
snapping back to the maximum width.

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

src/app/file_list.rs

@@ -169,9 +169,10 @@ impl App {
             .default_width(260.0)
             // A hard ceiling: the panel is sized from its content, so any row
             // that asks for more width than there is would otherwise push it
-            // wider every frame.
-            .width_range(160.0..=460.0)
-            .show(ctx, show_files, |ui| {
+            // wider every frame. We set a minimum width but no maximum to
+            // allow the user to make the panel as wide as they want.
+            .width_range(160.0..=f32::INFINITY)
+            .show_animated(ctx, show_files, |ui| {
                 // The default theme renders unselected list rows fairly dim; bump
                 // the widget text colours so file names stay legible (especially in
                 // dark mode) without affecting the rest of the app.