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>

data/input-remapper-focus.service

@@ -0,0 +1,16 @@
+[Unit]
+Description=Input Remapper focus-driven preset binding (per-user service)
+Documentation=https://github.com/sezanzeb/input-remapper
+# Runs in the graphical user session, talks to the root daemon over the system bus.
+After=graphical-session.target
+PartOf=graphical-session.target
+
+[Service]
+Type=dbus
+BusName=inputremapper.Focus
+ExecStart=/usr/bin/input-remapper-focus-service
+Restart=on-failure
+RestartSec=2
+
+[Install]
+WantedBy=graphical-session.target