feat: Add temporal support to node26

New for node 26.x versions, Node now ships with [temporal, a rust library that "provides standard objects and functions for working with dates and times."](https://github.com/tc39/proposal-temporal) by default.

["The Temporal API is now enabled by default in Node.js 26. Temporal is a modern date/time API for JavaScript that provides a more robust and feature-rich alternative to the legacy Date object."](https://nodejs.org/en/blog/release/v26.0.0#temporal-api) - node.js release notes

The official [node.js docs provide instructions on how to build with temporal support.](https://github.com/nodejs/node/blob/main/BUILDING.md#building-nodejs-with-temporal-support)

This flatpak extension should be updated to reflect the new standard and provide temporal support. To do so, rust needs to be available.
In addition, allowing for rust can allow for us to make build times faster, as we gain access to [mold.](https://github.com/flathub/org.freedesktop.Sdk.Extension.rust-stable/tree/branch/25.08#Mold)