Pin NPM package dependecy versions + npm ci

[davinotdavid]

What changed?

• Pinned NPM package dependency versions according to what was being used in package-lock.json:

- vue from ^3.4.29 to 3.5.32
- vue-i18n from ^11.1.2 to 11.3.2
- storybook (+ addons) from ^10.1.x to 10.3.5
- vite from ^7.0.5 to 7.3.2
- vitest from ^4.0.3 to 4.1.3
- typescript from ~5.9 to 5.9.3
- @playwright/test from ^1.44.1 to 1.59.1
- eslint from ^9.15.0 to 9.39.4

• Updated postcss from 8.5.9 to 8.5.15 due to security vulnerabilities
• Updated GH Action workflows to use npm ci instead of npm i since we have a checked-in package-lock.json

Why?

We should have stable package versions!

Applicable Issues

Closes #289

[devmount]

This looks good to me, Davi! Thanks for taking care of that!

However, I think it would be good to first merge #274 in and then pin the versions, since we had major version upgrades there 😇

[davinotdavid]

Thanks for the review @devmount as we chatted in Matrix, I believe it would be a better isolation if we merge this in then cut a patch version then merge your PR in and cut a patch version. What do you think?

[devmount]

@davinotdavid Yes, let's do it like this! I take care of updating #274 when we tagged the next patch release