fix: fix logical inconsistency in log entry formatting in index.html

[mdqst]

I noticed a logical inconsistency in the log entry formatting. The current code uses padStart(5) on newBlock.hash, which doesn't make sense for cryptographic hashes as they are typically much longer than 5 characters.

To address this, I replaced padStart(5) with slice(0, 5) to ensure only the first 5 characters of the hash are displayed. This change aligns with the intended behavior of showing a concise representation of the hash.

addLogEntry(`${newBlock.height}: ${newBlock.hash.slice(0, 5)}`);

This adjustment ensures the log entries are both meaningful and consistent.

[Twey]

Hi @mdqst, can you elaborate a bit more on what this change aims to accomplish? So long as the hash is longer than 5 characters long it seems that these calls should be equivalent — but slice will not behave as well if the hash is shorter (which it shouldn't be — but technically from our perspective this is a freeform string).