ESP32-S3 only one core mining?

LeafMiner 0.0.13

Device is LILYGO T-DISPLAY-S3. It can mine at speed about 75 kHps but from time to time it reports much smaller speed, about 37 kHps, like just one core is used for mining:

```
[I] Current: Hash accepted: 15
[D] Current: Hashrate: 37.66 kH/s
[D] Current: Hashrate: 37.80 kH/s
[D] Current: Hashrate: 37.84 kH/s
[D] Current: Hashrate: 37.80 kH/s
```

After reset it mines at full speed:

```
[I] Current: Job: 3039ac ready to be mined
[D] Current: Hashrate: 74.85 kH/s
[D] Current: Hashrate: 74.97 kH/s
[D] Current: Hashrate: 74.95 kH/s
[D] Current: Hashrate: 74.91 kH/s
```

Device is connected to USB port in PC. It is possible that this low speed is related to serial console, when I do not run terminal and serial buffer is full then hashing speed goes down. I noticed on display that speed was 35 kHps but when I started terminal, hashspeed increased to 75kHs, without reset...

I recorded such case, speed increased from 52kHps to 75 kHps when I started serial terminal:

```
$ miniterm /dev/ttyACM0 115200
--- Miniterm on /dev/ttyACM0 115200,8,N,1 ---
--- Quit: Ctrl+] | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H ---
d":77,"method":"mining.submit","params":["bc1quqr7agnx6e0k9kn8h24zfj5dueeurhzflt3qjg.LEAF","305c0e","39970631","66148939","007d6b8a"]}

[ICurrent: Hashrate: 52.14 kH/s
[D] Current: Hashrate: 74.97 kH/s
[D] Current: Hashrate: 74.95 kH/s
[D] Current: [D] Current: Hashrate: 74.93 kH/s
Hashrate: 74.93 kH/s
[D] Current: Hashrate: 74.98 kH/s
```

There are other issues with T-DISPLAY-S3:

* display is not reliable, sometime it just shows nothing or image is "broken", like it is not synchronized. Logo during boot is always displayed but when status screen is shown, I can see problems in some cases.
* LED do not blink, it shines in GREEN. There is an option in GUI to set LED BLINK, I configured the option to YES but LED do not blink...

This device was running NerdMiner_V2, v 1.6.3 for several weeks and it was reliable, no issue with display or LED or hashing speed... LED shines green when running NerdMiner, no difference.

I flashed LILYGO T-DISPALY-S3 with these commands (CLI):

```
# esptool.py write_flash -e 0 /dev/null # full chip ERASE...
esptool.py write_flash -z 0x0000 bootloader_lilygo-t-display-s3.bin
esptool.py write_flash -z 0x8000 partitions_lilygo-t-display-s3.bin
esptool.py write_flash -z 0x10000 firmware_lilygo-t-display-s3.bin
```

Reproduce on the LILYGO T-DISPLAY-S3 with LeafMiner 0.0.13, comparing mining with and without a serial terminal on /dev/ttyACM0. Review the flashing commands and observe the hashrate, status display, and LED behavior. Done means the reported regressions are consistently resolved on this device.

Written by the indexing model from the issue text.