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_artwork.py

@@ -6,7 +6,7 @@ import httpx
 import pytest
 from PIL import Image
 
-from somafm_tui import artwork
+from beefy_player import artwork
 
 
 def png_bytes(size=(400, 200)) -> bytes:
@@ -28,9 +28,11 @@ def test_protocol_detection() -> None:
     assert artwork.detect_protocol({"ZELLIJ": "1", "TERM_PROGRAM": "WezTerm"}) is None
     assert artwork.detect_protocol({"KITTY_PID": "1"}) == "tgp"
     assert artwork.detect_protocol({"NO_COLOR": "", "KITTY_WINDOW_ID": "1"}) is None
-    assert artwork.detect_protocol({"SOMAFM_IMAGES": "0", "KITTY_WINDOW_ID": "1"}) is None
-    assert artwork.detect_protocol({"SOMAFM_IMAGES": "tgp"}) == "tgp"
-    assert artwork.detect_protocol({"SOMAFM_IMAGES": "iterm2"}) == "iterm2"
+    assert artwork.detect_protocol({"BEEFY_IMAGES": "0", "KITTY_WINDOW_ID": "1"}) is None
+    assert artwork.detect_protocol({"BEEFY_IMAGES": "tgp"}) == "tgp"
+    assert artwork.detect_protocol({"BEEFY_IMAGES": "iterm2"}) == "iterm2"
+    # the pre-rename variable still works
+    assert artwork.detect_protocol({"SOMAFM_IMAGES": "0"}) is None
 
 
 def test_fit_image_crops_to_the_cell_box() -> None: