fix(tests): reconcile merge fallout with modified_ms field

The merge of main (#202 shared type-to-filter) brought in a test that
constructs SoundEntry without the modified_ms field this PR introduces,
breaking compilation; also restores rustfmt mod-declaration ordering in
app/mod.rs disturbed by the same merge.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: thewrz

src/app/filtering.rs

@@ -249,6 +249,7 @@ mod tests {
             format: AudioFormat::Wav,
             duration_ms: None,
             category: "Animals".into(),
+            modified_ms: None,
         }];
         app.sound_meta
             .set_display_name("goose", Some("Angry Bird".into()));

src/app/mod.rs

@@ -21,10 +21,10 @@ use crate::ui::theme::{self, Hh};
 use crate::ui::{now_playing, search_bar, slot_manager};
 use notices::{Notice, NoticeId, NoticeQueue};
 
-mod library_scan;
 /// Play-dispatch coordination (`request_play` / `handle_decoded` /
 /// `start_playback`), extracted to keep this file from growing (#151).
 mod filtering;
+mod library_scan;
 mod macros;
 #[cfg(test)]
 mod notice_tests;