Policy: Inheritance / continuation of possibly abandoned repositories

https://content.luanti.org/policy_and_guidance/#24-attempt-to-contribute-before-forking currently states:

> You should attempt to contribute upstream before forking a package. If you choose to fork, you should have a justification (different objectives, maintainer is unavailable, etc).

Contributors may abandon repositories, which is unfortunate when used broadly. For that reason I propose the following policy:

```
In case of absence of the author in charge, development of their content may be continued (= adopted) in a separate repository when meeting all of the following criteria:
1. Inactivity of the author for more than 2 years on all of the following: VCS platform (Version Control System, if applicable), ContentDB, Luanti forums.
* Inactivity is further defined by: no reaction to comments, issues, pull requests and other means of contributions in the aforementioned services.
2. (If applicable) unreachable by email or other means of contact outside of the Luanti and VCS platform for more than 1 month.
3. Long-term maintenance must be ensured.
* This criteria can be met by having the content as part of a sufficiently sized organisation or team.
If all criteria are met, the content name (author), VCS URL and related references in ContentDB and the Luanti forums may be changed to the maintained content.

Until the criteria are met, consider publishing the maintained content as a fork to ContentDB.
```
(The last sentence concerning "Luanti forums" is outside of the reach of ContentDB. However, it is generally the same people taking care of these services, thus this should be OK.)

Initial discussion: https://irc.luanti.org/luanti/2026-04-19#i_6323905
Input from rubenwardy: https://irc.luanti.org/luanti/2026-06-07#i_6328895

Read the current policy at content.luanti.org/policy_and_guidance/#24-attempt-to-contribute-before-forking, then review the linked IRC discussions for the unresolved policy context. Done means the adoption criteria and their scope are agreed and the relevant policy text is updated accordingly.

Written by the indexing model from the issue text.