perf(desktop): ship a .deb instead of an 80MB AppImage

Co-authored-by: Cursor <cursoragent@cursor.com>

services/api/internal/appupdate/appupdate_test.go

@@ -28,7 +28,7 @@ func TestPickClientFiles(t *testing.T) {
 	assert.Equal(t, "pipu-music-1.3.0.apk", files["android"].Name)
 	assert.Equal(t, "https://gitea/sum", files["android"].ChecksumURL)
 	assert.Equal(t, "pipu-music_1.3.0_x64-setup.exe", files["windows"].Name)
-	assert.Equal(t, "pipu-music_1.3.0_amd64.AppImage", files["linux"].Name)
+	assert.Equal(t, "pipu-music_1.3.0_amd64.deb", files["linux"].Name)
 	assert.Equal(t, "pipu-music_1.3.0_aarch64.dmg", files["macos"].Name)
 }