Ship a Dev Container / Codespaces setup for local contribution

## What

provide a ready-to-use Dev Container / Codespaces setup because local contribution setup is too hard.

## Want

- Provide a ready-to-use Dev Container / Codespaces setup because local contribution setup is too hard

## Ideas this came from

- [#8259 Provide devcontainer setup](https://github.com/goauthentik/authentik/issues/8259) — I am currently trying to contribute but the setup is really a pita. In my history I have used over 30 commands trying to get everything set up, installing syste
- [#16927 Simplify contribution setup (e.g. dev container)](https://github.com/goauthentik/authentik/issues/16927) — Contributing to the project is currently difficult due to the many dependencies required, even for testing small changes. It would be helpful to provide a ready

Review the current local contribution setup and the linked issues #8259 and #16927 to identify the dependencies and commands a contributor must reproduce. Define the Dev Container/Codespaces entry point around that setup, then verify that a fresh environment can follow the contribution workflow without the existing manual effort.

Written by the indexing model from the issue text.