UART TX and RX lose synchronization after 100+ continuous bytes

[ArjunPShetty]

When transmitting more than 100 bytes continuously, the receiver occasionally loses synchronization, causing frame errors.

Steps to Reproduce:

1. Run ./sim/run_simulation.sh loopback
2. Send 200 bytes of continuous data (0x00 to 0xC8)
3. Observe frame errors after ~120 bytes

Expected Behavior:
All bytes should be received correctly without frame errors.

Actual Behavior:
Frame errors occur after approximately 120 bytes of continuous transmission.

Environment:

• Simulator: Icarus Verilog 11.0
• Testbench: uart_loopback_tb.v
• Baud Rate: 115200 bps