feat: add update_meta to SongRepositoryPort and PATCH /songs/{id}

crates/infrastructure/persistence/src/lib.rs

@@ -102,6 +102,58 @@ impl SongRepositoryPort for SqliteSongRepository {
             Ok(())
         }
     }
+
+    async fn update_meta(
+        &self,
+        id: Uuid,
+        title: Option<&str>,
+        artist: Option<&str>,
+        original_key: Option<&str>,
+    ) -> Result<SongSummary, RepositoryError> {
+        let id_str = id.to_string();
+
+        let row = sqlx::query_as::<_, SongRow>(
+            "SELECT id, title, artist, original_key, preview_chords, body FROM songs WHERE id = ?"
+        )
+        .bind(&id_str)
+        .fetch_optional(&self.pool)
+        .await
+        .map_err(|e| RepositoryError::Internal(e.to_string()))?
+        .ok_or(RepositoryError::NotFound)?;
+
+        let mut song: Song = serde_json::from_str(&row.body)
+            .map_err(|e| RepositoryError::Internal(e.to_string()))?;
+        if let Some(t) = title { song.meta.title = t.to_string(); }
+        if let Some(a) = artist { song.meta.artist = a.to_string(); }
+        if let Some(k) = original_key { song.meta.original_key = Some(k.to_string()); }
+        let new_body = serde_json::to_string(&song)
+            .map_err(|e| RepositoryError::Internal(e.to_string()))?;
+
+        let new_title = title.unwrap_or(&row.title);
+        let new_artist = artist.unwrap_or(&row.artist);
+        let new_key: Option<&str> = original_key.or(row.original_key.as_deref());
+
+        sqlx::query(
+            "UPDATE songs SET title = ?, artist = ?, original_key = ?, body = ? WHERE id = ?"
+        )
+        .bind(new_title)
+        .bind(new_artist)
+        .bind(new_key)
+        .bind(&new_body)
+        .bind(&id_str)
+        .execute(&self.pool)
+        .await
+        .map_err(|e| RepositoryError::Internal(e.to_string()))?;
+
+        let preview_chords: Vec<String> = serde_json::from_str(&row.preview_chords)
+            .map_err(|e| RepositoryError::Internal(e.to_string()))?;
+
+        Ok(SongSummary {
+            id,
+            meta: song.meta,
+            preview_chords,
+        })
+    }
 }
 
 #[async_trait]