fix(ui): keep Bandcamp link across history refreshes

tests/test_app.py

@@ -159,6 +159,63 @@ async def test_stage_shows_bandcamp_link_only_when_present() -> None:
         assert "Bandcamp" not in rendered_text(app)
 
 
+@pytest.mark.asyncio
+async def test_bandcamp_link_survives_history_refresh(monkeypatch) -> None:
+    app = SomaFMApp(autoplay=False, offline=True, audio=False)
+    async with app.run_test(size=(110, 40)) as pilot:
+        await pilot.pause()
+        station = app.current
+        assert station is not None
+        url = "https://jensbuchert.bandcamp.com/track/rauschebart"
+        old_song = Song(
+            title="Rauschebart",
+            artist="Jens Buchert",
+            album="Gravity",
+            bandcamp_url=url,
+        )
+        station.now_playing = old_song
+        station.history = [old_song]
+
+        async def fake_fetch_history(client, station_id):
+            assert station_id == station.id
+            return [
+                Song(
+                    title="Rauschebart",
+                    artist="Jens Buchert",
+                    album="Gravity",
+                )
+            ]
+
+        monkeypatch.setattr("somafm_tui.app.api.fetch_history", fake_fetch_history)
+        worker = app._fetch_history(station.id)
+        await worker.wait()
+        await pilot.pause()
+
+        assert station.now_playing is not None
+        assert station.now_playing is not old_song
+        assert station.now_playing.bandcamp_url == url
+        assert "Bandcamp" in rendered_text(app)
+
+
+@pytest.mark.asyncio
+async def test_cached_bandcamp_link_is_reapplied_to_new_song() -> None:
+    app = SomaFMApp(autoplay=False, offline=True, audio=False)
+    async with app.run_test(size=(110, 40)) as pilot:
+        await pilot.pause()
+        station = app.current
+        assert station is not None
+        url = "https://jensbuchert.bandcamp.com/track/rauschebart"
+        song = Song(title="Rauschebart", artist="Jens Buchert", album="Gravity")
+        app._bandcamp_urls[f"{station.id}|{song.key()}"] = url
+        station.now_playing = song
+
+        app._update_bandcamp()
+        await pilot.pause()
+
+        assert song.bandcamp_url == url
+        assert "Bandcamp" in rendered_text(app)
+
+
 @pytest.mark.asyncio
 async def test_media_session_commands_drive_the_app() -> None:
     app = SomaFMApp(autoplay=False, offline=True, audio=False)