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_mpris.py

@@ -4,7 +4,7 @@ import queue
 
 import pytest
 
-from somafm_tui import mpris
+from beefy_player import mpris
 
 
 def test_build_metadata() -> None:
@@ -17,16 +17,16 @@ def test_build_metadata() -> None:
         stream_url="https://ice2.somafm.com/groovesalad-256-mp3",
         track_key="groovesalad|Jens Buchert|Rauschebart|Gravity",
     )
-    assert metadata["mpris:trackid"].value.startswith("/org/somafm/track/")
+    assert metadata["mpris:trackid"].value.startswith("/org/beefyplayer/track/")
     assert metadata["xesam:title"].value == "Rauschebart"
     assert metadata["xesam:artist"].value == ["Jens Buchert"]
     assert metadata["xesam:album"].value == "Gravity"
     assert metadata["mpris:artUrl"].value == "https://example.com/art.jpg"
     assert metadata["xesam:url"].value.startswith("https://ice2.")
-    assert metadata["xesam:comment"].value == ["SomaFM · Groove Salad"]
+    assert metadata["xesam:comment"].value == ["Beefy Player · Groove Salad"]
 
     minimal = mpris.build_metadata(station="X", title="", artist="")
-    assert minimal["xesam:artist"].value == ["SomaFM"]
+    assert minimal["xesam:artist"].value == ["Beefy Player"]
     assert "xesam:album" not in minimal
     assert "mpris:artUrl" not in minimal