chore: upgrade prettier from 2.x to 3.x

[hb2708]

Summary

Upgrade prettier from 2.1.2 to 3.x. This will cause formatting changes across the codebase due to updated defaults and improved formatting rules.

Current → Target

Package	Current	Latest
prettier	2.1.2	3.8.1
eslint-plugin-prettier	4.2.1	5.5.5
eslint-config-prettier	8.5.0	10.1.8

Why Upgrade

• v2 is no longer maintained
• v3 has better formatting for many edge cases
• Improved TypeScript and JSX formatting

Migration Steps

1. Install new versions together (eslint-prettier integration must be compatible):

   yarn add --dev prettier@latest eslint-plugin-prettier@latest eslint-config-prettier@latest

2. Review config changes — some defaults changed in v3:
   • trailingComma default changed from "es5" to "all"
   • Review .prettierrc or prettier config if one exists
3. Reformat the entire codebase in a single commit:

   npx prettier --write .

4. Commit the formatting changes separately — this makes git blame cleaner. Consider adding a .git-blame-ignore-revs file with the reformat commit hash.
5. Run yarn ci to verify lint + tests pass with the new formatting

⚠️ Note

This will produce a large diff touching many files. It's best done:

• As a standalone PR with no other changes
• When there are few open PRs to minimize merge conflicts

Files Affected

• Nearly every .ts/.tsx/.js file (formatting changes)
• package.json — dependency versions
• Possibly .prettierrc or prettier config

References

• Prettier 3.0 Blog Post
• Changelog