Esp-WEB-Tools and SPIFFS

Good morning,
I cannot flash a spiffs file containing a website with ESP-Web-Tools. The firmware part flashes correctly but not the SPIFFS file. I have to use the Arduino IDE or VSCode and PlateformIO.
Here is my manifest:
```json
{
"name": "ESPHome",
"builds": [
{
"chipFamily": "ESP32",
"improv": false,
"parts": [
{ "path": "bootloader.bin", "offset": 4096 },
{ "path": "partitions.bin", "offset": 32768 },
{ "path": "boot_app0.bin", "offset": 57344 },
{ "path": "firmware.bin", "offset": 65536 },
{ "path": "spiffs.bin", "offset": 2686976}
]
},
{
"chipFamily": "ESP8266",
"parts": [
{ "path": "esp8266.bin", "offset": 0 }
]
}
]
}
```
and here is what the Arduino IDE does:
```
For the spiffs part :

Serial port COM17
Connecting.....
Chip is ESP32-D0WD-V3 (revision v3.0)
Features: WiFi, BT, Dual Core, 240MHz, VRef calibration in efuse, Coding Scheme None
Crystal is 40MHz
MAC: b4:8a:0a:63:70:38
Uploading stub...
Running stub...
Stub running...
Changing baud rate to 921600
Changed.
Configuring flash size...
Auto-detected Flash size: 16MB
Flash will be erased from 0x00290000 to 0x003effff...
Compressed 1441792 bytes to 7020...
Writing at 0x00290000... (100 %)
Wrote 1441792 bytes (7020 compressed) at 0x00290000 in 8.2 seconds (effective 1414.2 kbit/s)...
Hash of data verified.
```