feat: add SongSearchService and GET /songs?q= search endpoint

crates/infrastructure/persistence/src/lib.rs

@@ -1,11 +1,12 @@
 use async_trait::async_trait;
 use domain::{
-    RepositoryError, Song, SongMeta, SongRepositoryPort, SongSummary, StoredSong,
+    RepositoryError, Song, SongMeta, SongRepositoryPort, SongSearchPort, SongSummary, StoredSong,
     song_preview_chords,
 };
 use sqlx::SqlitePool;
 use uuid::Uuid;
 
+#[derive(Clone)]
 pub struct SqliteSongRepository {
     pool: SqlitePool,
 }
@@ -122,6 +123,43 @@ impl SongRepositoryPort for SqliteSongRepository {
     }
 }
 
+#[async_trait]
+impl SongSearchPort for SqliteSongRepository {
+    async fn search(&self, query: &str) -> Result<Vec<SongSummary>, RepositoryError> {
+        let pattern = format!("%{}%", query);
+        let rows = sqlx::query_as::<_, SongRow>(
+            "SELECT id, title, artist, original_key, preview_chords, body FROM songs \
+             WHERE title LIKE ? OR artist LIKE ? ORDER BY created_at DESC"
+        )
+        .bind(&pattern)
+        .bind(&pattern)
+        .fetch_all(&self.pool)
+        .await
+        .map_err(|e| RepositoryError::Internal(e.to_string()))?;
+
+        rows.into_iter()
+            .map(|row| {
+                let id = Uuid::parse_str(&row.id)
+                    .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: SongMeta {
+                        title: row.title,
+                        artist: row.artist,
+                        original_key: row.original_key,
+                        capo: None,
+                        tuning: None,
+                        tempo: None,
+                    },
+                    preview_chords,
+                })
+            })
+            .collect()
+    }
+}
+
 pub struct SqliteRepositoryFactory;
 
 impl SqliteRepositoryFactory {