feat(app-binding): lier les presets aux applications

Ajoute la configuration des associations application/preset, le service de suivi du focus, l'intégration GUI et les fichiers d'installation nécessaires.

Ajoute les tests unitaires ciblés des bindings, du service de focus, des migrations et des composants GUI associés.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

inputremapper/focus/backends/__init__.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# input-remapper - GUI for device specific keyboard mappings
+# Copyright (C) 2025 sezanzeb <b8x45ygc9@mozmail.com>
+#
+# This file is part of input-remapper.
+#
+# input-remapper is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# input-remapper is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with input-remapper.  If not, see <https://www.gnu.org/licenses/>.
+
+"""Focus detection backends, one per compositor / display server."""