Create Documentations for future references and contributors

[chetanr25]

Docs: getting-started guide for the server repo

Context

After the restructure, the existing docs no longer match the layout. For now we only need one thing: a contributor can clone the server repo and get it running. Nothing else.

Goal

A single, short getting-started guide under docs/, following the Diátaxis how-to style (task-focused, on one screen).

docs/
  index.md
  dev/
    how-to-quick-start.md

Tasks

• docs/dev/how-to-quick-start.md: clone → make init → make up → hit the API. Reflect the new init/up split and the new backend/ layout.
• docs/index.md: tiny landing page linking to the quick-start.
• Remove or archive doc pages made stale by the restructure / frontend split.