feat(idf): config BT Classic HFP-HF + partitions

Ajoute sdkconfig.defaults (BT Bluedroid BR/EDR + HFP-HF data path HCI,
flash 4 MB) et partitions.csv custom 4 MB sans OTA. Les 5 clés BT cibles
valent =y après régénération et build réussi (Project build complete).

partitions.csv

@@ -0,0 +1,4 @@
+# Name,   Type, SubType, Offset,   Size,     Flags
+nvs,      data, nvs,     0x9000,   0x6000,
+phy_init, data, phy,     0xf000,   0x1000,
+factory,  app,  factory, 0x10000,  0x2F0000,

sdkconfig.defaults

@@ -0,0 +1,25 @@
+# Cible
+CONFIG_IDF_TARGET="esp32"
+
+# Flash 4 MB (carte A1S) — requis pour que la partition factory 3 MB tienne
+CONFIG_ESPTOOLPY_FLASHSIZE_4MB=y
+CONFIG_ESPTOOLPY_FLASHSIZE="4MB"
+
+# Partitions
+CONFIG_PARTITION_TABLE_CUSTOM=y
+CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="partitions.csv"
+
+# Bluetooth : Bluedroid, BR/EDR only (pas de BLE), HFP-HF, data path HCI
+CONFIG_BT_ENABLED=y
+CONFIG_BT_BLUEDROID_ENABLED=y
+CONFIG_BT_CLASSIC_ENABLED=y
+CONFIG_BTDM_CTRL_MODE_BR_EDR_ONLY=y
+CONFIG_BT_HFP_ENABLE=y
+CONFIG_BT_HFP_CLIENT_ENABLE=y
+CONFIG_BT_HFP_AUDIO_DATA_PATH_HCI=y
+
+# Confort logs
+CONFIG_LOG_DEFAULT_LEVEL_INFO=y
+
+# Watchdog : tolérer la boucle de heartbeat
+CONFIG_ESP_TASK_WDT_INIT=n