refactor!: rename somafm-tui to beefy-player

The app is now a general internet-radio player rather than a SomaFM client, so the package, console script, MPRIS identity, mpv namespaces, macOS tap names, XDG directories and docs all move to beefy-player.

Environment variables are now BEEFY_* (the old SOMAFM_* spellings are still honoured) and an existing ~/.config/somafm-tui/config.json is migrated on first run, so favourites and volume survive the rename.

The visible interface is untouched: same layout, same logo, same keys.

tests/test_theme.py

@@ -5,15 +5,15 @@ from pathlib import Path
 
 import pytest
 
-from somafm_tui.app import SomaFMApp
-from somafm_tui.widgets.header import HeaderBar
-from somafm_tui.widgets.search import SearchInput
-from somafm_tui.widgets.spectrum import SpectrumPanel
-from somafm_tui.widgets.stage import StagePanel
-from somafm_tui.widgets.station_list import StationList
-from somafm_tui.widgets.status import StatusBar
+from beefy_player.app import BeefyPlayerApp
+from beefy_player.widgets.header import HeaderBar
+from beefy_player.widgets.search import SearchInput
+from beefy_player.widgets.spectrum import SpectrumPanel
+from beefy_player.widgets.stage import StagePanel
+from beefy_player.widgets.station_list import StationList
+from beefy_player.widgets.status import StatusBar
 
-PACKAGE = Path(__file__).resolve().parents[1] / "somafm_tui"
+PACKAGE = Path(__file__).resolve().parents[1] / "beefy_player"
 
 
 def test_no_rgb_colors_in_source() -> None:
@@ -29,7 +29,7 @@ def test_no_rgb_colors_in_source() -> None:
 
 @pytest.mark.asyncio
 async def test_backgrounds_use_terminal_default_and_borders_are_ansi() -> None:
-    app = SomaFMApp(autoplay=False, offline=True, audio=False)
+    app = BeefyPlayerApp(autoplay=False, offline=True, audio=False)
     async with app.run_test(size=(100, 30)) as pilot:
         await pilot.pause()