This request is a major optimization for Arduino_Code with almost 135%+ performance compared with the original version

Highlights:

ASM Implementation: The SHA1 compression loop has been rewritten in Assembly to reduce clock cycles per round
Register Management Optimization: Hand-optimized usage of the 32 available 8-bit registers
This prevents "register spilling" (when the compiler moves data to RAM/Stack due to lack of free registers), significantly reducing ld/st (load/store) cycles
Loop Unrolling: Strategic loop unrolling to maximize execution speed on ATmega328P and similar chips.
Binary Size: Efficient code that fits comfortably within the memory limits of Arduino Nano/Uno/Pro Mini.
Lower Dynamic memory (-2/3%) and flash (-8%) use compared to the original code (40% flash, 21% memory)
Architecture-Safe: The implementation is wrapped in #if defined(AVR) guards, ensuring it only compiles for 8-bit AVR
boards and maintains zero impact/full compatibility with ESP8266, ESP32, and other architectures.

Benchmarks (Arduino UNO)

Hashrate: stable 785-779 hs (the original was 333hs)
Shares: no rejected shares or other code related bugs until now
Performance gain: 135%+
Temperature: Same as the original file
Assigned diff: 128 (ARM) original was 10 (AVR)

Stability:

Tested for some hours straight with zero rejected shares or calculation errors.
Completely compatible with the official Duino-Coin AVR Miner Python script.
The server successfully recognizes the performance boost, upgrading the difficulty from 10 to 128.

one of my tests:

IDE output:
Sketch: 10,550 bytes (32%) of program storage space.
Dynamic Memory: 394 bytes (19%) of RAM.
Leaves 1,654 bytes for local variables.

Notes:
This is my first time making a PR on GitHub. If I made any mistakes regarding the commit structure or formatting, please let me know and I will fix them as soon as possible. If you find any errors or instability in the code, I am ready to provide fixes
i just forgot to add, but this script was inspired by JK Rolling's code (the max 721hs one), thanks to them!