[TO DO] Layer (back) DSL from 2024

[Sing-Li]

Layer back the excellent DSL implementation created by @anjy7 from 2024.

This should be significantly easier because:

1. @anjy7 has a working DSL already on the old platform, you'll not have to do it from scratch (just copy)
2. only the generation part of the DSL needs to be ported (easy); the code manipulation part (used to hack into the build pipeline of nextjs to cause the page-based system to behave somewhat component-like) can be totally abandoned
3. we have eliminated the complex CMS that took a lot of effort to accommodate (now it is all plain old JSON)
4. we have simplified deployment loop from our experience and the complex "update cluster" vs "rendering cluster" contention is no longer relevant