hls: cargo fmt + clippy::cloned_ref_to_slice_refs

Pure mechanical pass on the files this branch added/modified:
rustfmt reflow of a few long lines / chains, and the one
non-pre-existing clippy warning — replacing
`&[rel_path.clone()]` with `std::slice::from_ref(&rel_path)` in
`handlers::video::generate_video` to avoid the alloc + clone for a
single-element slice.

All 707 tests still pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/handlers/video.rs

@@ -80,11 +80,10 @@ pub async fn generate_video(
         return HttpResponse::BadRequest().finish();
     };
 
-    let preferred_library =
-        libraries::resolve_library_param(&app_state, body.library.as_deref())
-            .ok()
-            .flatten()
-            .unwrap_or_else(|| app_state.primary_library());
+    let preferred_library = libraries::resolve_library_param(&app_state, body.library.as_deref())
+        .ok()
+        .flatten()
+        .unwrap_or_else(|| app_state.primary_library());
 
     // Try the resolved library first, then fall back to any other library
     // that actually contains the file — handles union-mode requests where
@@ -122,7 +121,11 @@ pub async fn generate_video(
     // already-ingested videos.
     let hash_from_db: Option<String> = {
         let mut dao = exif_dao.lock().expect("Unable to lock ExifDao");
-        match dao.get_exif_batch(&context, Some(resolved_library_id), &[rel_path.clone()]) {
+        match dao.get_exif_batch(
+            &context,
+            Some(resolved_library_id),
+            std::slice::from_ref(&rel_path),
+        ) {
             Ok(rows) => rows.into_iter().next().and_then(|r| r.content_hash),
             Err(e) => {
                 warn!(