fix(library): extract track/disc number from file tags during backfill import

insert_qobuz_cached_track_direct was hardcoding track_number to 0,
causing all imported tracks to show wrong numbers. Now accepts
track_number and disc_number params, and both callers (backfill
downloads and offline cache sync) extract metadata from the audio
file via MetadataExtractor before inserting.

Also fix LocalLibraryView to use || instead of ?? for track_number
fallback, so 0 correctly falls back to index-based numbering.

Closes #147

crates/qbz-library/src/database.rs

@@ -3348,6 +3348,8 @@ impl LibraryDatabase {
         file_path: &str,
         bit_depth: Option<u32>,
         sample_rate: Option<f64>,
+        track_number: Option<u32>,
+        disc_number: Option<u32>,
     ) -> Result<(), LibraryError> {
         use std::time::SystemTime;
 
@@ -3378,8 +3380,8 @@ impl LibraryDatabase {
                 artist,
                 album.unwrap_or("Unknown Album"),
                 artist, // Use artist as album_artist for proper grouping
-                0, // track_number - will be updated if metadata is available
+                track_number.map(|v| v as i64),
-                None::<u32>, // disc_number
+                disc_number.map(|v| v as i64),
                 None::<u32>, // year
                 duration_secs as i64,
                 "flac", // Default format for downloads

src-tauri/src/library/commands.rs

@@ -2620,7 +2620,16 @@ pub async fn library_backfill_downloads(
             continue;
         }
 
-        // Track doesn't exist - insert as new
+        // Track doesn't exist - extract track/disc number from file tags
+        let (track_num, disc_num) = match MetadataExtractor::extract(std::path::Path::new(&file_path)) {
+            Ok(meta) => (meta.track_number, meta.disc_number),
+            Err(e) => {
+                log::warn!("Could not extract metadata from {}: {}", file_path, e);
+                (None, None)
+            }
+        };
+
+        // Insert as new
         match library_db.insert_qobuz_cached_track_direct(
             track_id,
             &title,
@@ -2630,6 +2639,8 @@ pub async fn library_backfill_downloads(
             &file_path,
             bit_depth,
             sample_rate,
+            track_num,
+            disc_num,
         ) {
             Ok(_) => report.added_tracks += 1,
             Err(e) => {

src-tauri/src/offline_cache/commands.rs

@@ -11,6 +11,7 @@ use crate::offline_cache::metadata::{
     embed_artwork, fetch_complete_metadata, organize_cached_file, save_album_artwork,
     write_flac_tags,
 };
+use crate::library::MetadataExtractor;
 use crate::offline_cache::OfflineCacheState;
 
 /// Post-process a cached track: fetch metadata, tag FLAC, embed artwork, organize files
@@ -876,7 +877,16 @@ pub async fn sync_offline_cache_to_library(
                     already_present += 1;
                 }
                 Ok(false) => {
-                    // Insert into library with basic metadata
+                    // Extract track/disc number from file tags
+                    let (track_num, disc_num) = match MetadataExtractor::extract(std::path::Path::new(&track.file_path)) {
+                        Ok(meta) => (meta.track_number, meta.disc_number),
+                        Err(e) => {
+                            log::warn!("Could not extract metadata from {}: {}", track.file_path, e);
+                            (None, None)
+                        }
+                    };
+
+                    // Insert into library with metadata from file tags
                     match library_db.insert_qobuz_cached_track_direct(
                         track.track_id,
                         &track.title,
@@ -886,6 +896,8 @@ pub async fn sync_offline_cache_to_library(
                         &track.file_path,
                         track.bit_depth,
                         track.sample_rate,
+                        track_num,
+                        disc_num,
                     ) {
                         Ok(_) => {
                             log::info!(

src/lib/components/views/LocalLibraryView.svelte

@@ -3250,7 +3250,7 @@
           {/if}
           {#each section.tracks as track, index (track.id)}
             <TrackRow
-              number={track.track_number ?? index + 1}
+              number={track.track_number || index + 1}
               title={track.title}
               artist={track.artist !== selectedAlbum?.artist ? track.artist : undefined}
               duration={formatDuration(track.duration_secs)}