Reduce reallocation in buffer expansion

[wyattgill9]

Summary

Optimizes buffer growth strategy by reducing unnecessary reallocations realloc() (calls) improving performance for large reads, with no small read difference

Changes: run.c

• Changed buffer expansion logic for efficiency.
• Reduces realloc calls, improving large read performance.

Code changed

if (bytes.len == capacity - 1) {
  capacity *= 2;
  bytes.buf = realloc(bytes.buf, capacity);
}

=>

if (bytes.len + 16 >= capacity) {  // Grow in larger increments
  capacity = capacity * 2 + 128;   // Avoid frequent realloc
  bytes.buf = realloc(bytes.buf, capacity);
}

I can tweak the exact numbers, but this is a good start