Init photobooth - borne photo evenementielle RPi4

Backend FastAPI complet : camera gphoto2, filtres/overlays Pillow,
chroma key OpenCV, multi-shot/collage, GIF, impression CUPS, email SMTP,
QR code. Frontend web vanilla (HTML/CSS/JS) pour Chromium kiosk.
Menu admin cache (appui long coin ecran). Toutes les fonctionnalites
activables/desactivables. Scripts install + systemd pour RPi4.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/config.py

@@ -0,0 +1,52 @@
+import json
+import os
+import shutil
+from pathlib import Path
+
+RACINE = Path(__file__).resolve().parent.parent
+CHEMIN_CONFIG = RACINE / "data" / "config.json"
+CHEMIN_CONFIG_DEFAUT = RACINE / "data" / "config.defaut.json"
+DOSSIER_PHOTOS = RACINE / "data" / "photos"
+DOSSIER_EXPORTS = RACINE / "data" / "exports"
+DOSSIER_OVERLAYS = RACINE / "frontend" / "assets" / "overlays"
+DOSSIER_FONDS = RACINE / "frontend" / "assets" / "backgrounds"
+
+
+def charger_config() -> dict:
+    """Charge la configuration depuis config.json."""
+    if not CHEMIN_CONFIG.exists():
+        if CHEMIN_CONFIG_DEFAUT.exists():
+            shutil.copy(CHEMIN_CONFIG_DEFAUT, CHEMIN_CONFIG)
+        else:
+            return {}
+    with open(CHEMIN_CONFIG, "r", encoding="utf-8") as f:
+        return json.load(f)
+
+
+def sauvegarder_config(config: dict):
+    """Sauvegarde la configuration dans config.json."""
+    CHEMIN_CONFIG.parent.mkdir(parents=True, exist_ok=True)
+    with open(CHEMIN_CONFIG, "w", encoding="utf-8") as f:
+        json.dump(config, f, ensure_ascii=False, indent=2)
+
+
+def mettre_a_jour_config(modifications: dict) -> dict:
+    """Met a jour la configuration avec les modifications fournies (merge profond)."""
+    config = charger_config()
+    _merge_profond(config, modifications)
+    sauvegarder_config(config)
+    return config
+
+
+def _merge_profond(base: dict, modifications: dict):
+    """Fusionne recursivement les modifications dans la base."""
+    for cle, valeur in modifications.items():
+        if cle in base and isinstance(base[cle], dict) and isinstance(valeur, dict):
+            _merge_profond(base[cle], valeur)
+        else:
+            base[cle] = valeur
+
+
+# Initialisation des dossiers au chargement du module
+for dossier in [DOSSIER_PHOTOS, DOSSIER_EXPORTS, DOSSIER_OVERLAYS, DOSSIER_FONDS]:
+    dossier.mkdir(parents=True, exist_ok=True)