Define deprecation process

User Story

As maintainer of an organizational project, I want to know the process of deprecating/archiving a project, so that I know what would happen in case I initiate it.

Approach (deliberately narrow)

The default is: the TSC does not initiate deprecation. A maintainer who answers the annual ping (see #210) and confirms they still care about the project — however busy they are — is done; that answer is sufficient on its own, nothing else happens.

The TSC only gets involved in two specific cases:

1. Voluntary retirement: a maintainer themselves asks the TSC/dedicated group for help retiring their project. The TSC assists on request, it does not propose this unprompted.
2. Fallback, no response at all: the annual ping from #210 goes fully unanswered after the agreed number of reminders. This is the one case self-attestation structurally cannot cover — nobody is left to ask — and it is also where the foundation's own backstop responsibility (controlling the group id, security releases per typelevel/tsc#196) requires someone to act, since an unmaintained Organization Project left untouched quietly implies a support guarantee that no longer holds.

Activity level, release frequency, or any other "health" signal is explicitly not a trigger on its own — only confirmed non-response is.

Acceptance Criteria

• Default rule documented: the TSC does not initiate deprecation for a maintainer who confirms continued commitment, regardless of activity level (separate from #196 security-backstop obligations, which can still require action independently).
• Voluntary path documented: a maintainer may ask the dedicated group to help run the retirement process for their own project.
• Fallback path documented: triggered only when the annual ping (linked ticket) goes fully unanswered; defines the steps from there (further outreach attempt, downgrade Organization → Affiliate, archival, public announcement).
• A dedicated group of 3 people is defined, responsible for handling both the voluntary and fallback paths.
• The process is documented (e.g. as a markdown doc in this repo, similar to resources/).
• The process is communicated to all maintainers of Typelevel Organization projects, so they know exactly what does and does not trigger it.

I want to declare: I used AI to challenge my thinking on this proposal and to help me write it clearly in English.