This PR changes the SQLite database setting to use WAL (Write-Ahead
Logging) mode. From what I can tell, it should be an easy performance
improvement with no real downside for our case. Documentation is here:
https://sqlite.org/wal.html

Also, the [docs for
better-sqlite3](https://www.npmjs.com/package/better-sqlite3) explicitly
recommend it:

> Though not required, it is generally important to set the WAL pragma
for performance reasons.

I came across this as I was looking into the issue where the chat code
blocks slow down Dyad's framerate. I'm not entirely sure whether this is
related, but I did notice that sometimes database calls were taking a
lot longer than I expected, and that would cause Dyad's framerate to
drop significantly on my machine. This change seems to be an improvement
in that regard, so it might also have an effect on the code blocks issue
as well.

It's hard to accurately benchmark this because its effect is only
substantial when there are multiple database calls going on at the same
time. I can definitely attempt a benchmark if that would be worthwhile
though.
<!-- devin-review-badge-begin -->

---

<a href="https://app.devin.ai/review/dyad-sh/dyad/pull/3140"
target="_blank">
  <picture>
<source media="(prefers-color-scheme: dark)"
srcset="https://static.devin.ai/assets/gh-open-in-devin-review-dark.svg?v=1">
<img
src="https://static.devin.ai/assets/gh-open-in-devin-review-light.svg?v=1"
alt="Open with Devin">
  </picture>
</a>
<!-- devin-review-badge-end -->