feat: implement librespot-powered search

docs/librespot_client.md

@@ -189,6 +189,24 @@ playlist_expanded = client.get_playlist("spotify:playlist:...", expand_items=Tru
 ```
 
 
+### search(query, limit=10, country=None, locale=None, catalogue=None, image_size=None) -> dict
+Performs a full-featured search using librespot's SearchManager.
+
+- Country precedence: explicit `country` > session country code > unset
+- Returns librespot's JSON-like mapping (tracks, albums, artists, playlists, etc.)
+
+Usage:
+
+```python
+res = client.search(
+    "artist:daft punk track:one more time",
+    limit=10,
+    country="US",
+    locale="en_US"
+)
+tracks = res.get("tracks", {}).get("items", [])
+```
+
 ## Concurrency and caching
 
 - When expanding tracks for albums/playlists, the client concurrently fetches missing track objects using a `ThreadPoolExecutor` with up to `max_workers` threads (default 16).