fix(box3): SPIFFS mount + canal WiFi configurable pour relais ESP-NOW

scenario_server.c : SPIFFS_LABEL valait "storage" alors que la partition
s'appelle "spiffs" (partitions.csv) → esp_vfs_spiffs_register échouait en
ESP_ERR_NOT_FOUND, la BOX-3 ne pouvait persister aucun scénario reçu (HTTP
500 + relais ESP-NOW sans effet). Corrigé en "spiffs".

main.c + Kconfig.projbuild : ajout de CONFIG_ZACUS_WIFI_CHANNEL (défaut
0 = auto) câblé sur wifi_config.sta.channel. Sur réseau multi-AP / mesh
(même SSID sur plusieurs canaux), permet de forcer la BOX-3 co-canal avec
le master — prérequis ESP-NOW.

Validé sur matériel : master (ch6) → POST /game/scenario/relay → la BOX-3
reçoit + réassemble (679 B) via scenario_mesh, monte SPIFFS, hot-load OK,
reboot pour appliquer.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

box3_voice/main/Kconfig.projbuild

@@ -12,6 +12,16 @@ menu "Zacus BOX-3 Voice Configuration"
         help
             WiFi password. Leave empty for open networks.
 
+    config ZACUS_WIFI_CHANNEL
+        int "WiFi channel hint (0 = auto)"
+        default 0
+        range 0 13
+        help
+            Bias the STA scan to start on this channel (1-13). Set this to the
+            master's WiFi channel so ESP-NOW peers land co-channel — required
+            for the scenario relay on multi-AP / mesh networks where the same
+            SSID is broadcast on several channels. 0 = auto (scan all).
+
     config ZACUS_VOICE_BRIDGE_URL
         string "Voice Bridge WebSocket URL"
         default "ws://192.168.0.119:8200/voice/ws"

box3_voice/main/main.c

@@ -89,6 +89,7 @@ static esp_err_t wifi_init_sta(void)
             .ssid     = CONFIG_ZACUS_WIFI_SSID,
             .password = CONFIG_ZACUS_WIFI_PASSWORD,
             .threshold.authmode = WIFI_AUTH_WPA2_PSK,
+            .channel  = CONFIG_ZACUS_WIFI_CHANNEL,  /* co-channel master for ESP-NOW relay (0 = auto) */
         },
     };
 

box3_voice/main/scenario_server.c

@@ -25,7 +25,7 @@
 #define TAG "scenario_srv"
 
 #define MAX_SCENARIO_BYTES (64 * 1024)
-#define SPIFFS_LABEL       "storage"
+#define SPIFFS_LABEL       "spiffs"
 #define SPIFFS_BASE        "/spiffs"
 #define SCENARIO_PATH      SPIFFS_BASE "/scenario.json"
 #define SCENARIO_BAK       SPIFFS_BASE "/scenario.bak"