feat(ycst-org-uk): move the two ycst repos out of yo61

[robinbowes]

Moves ycst-admin-docs and ycst-website-testing from yo61 to ycst-org-uk
as board-docs and website-testing, and grants admin through the admins
team on both instead of naming PlanetSeth directly.

Do not merge yet. The repos must be transferred and renamed on GitHub
first. github_repository takes its owner from the provider, so Terraform
cannot do the move; one moved block per repo then carries all four of its
state instances across the provider alias and the renamed for_each key.

Merging before the transfer creates a window where the plan proposes to
create ycst-org-uk/board-docs; applying that would leave an empty repo whose
name then blocks the real transfer. Transferring first inverts the failure into
a harmless plan against yo61, since the API redirects the old paths.

The plan for this must be unscoped — a cross-org moved block cannot be
targeted to one side (Moved resource instances excluded by targeting).

Expected plan, and nothing else:

• zero destroys
• eight moves — four instances per repo
• two changes, both github_repository_collaborators.this: board-docs drops
  PlanetSeth's direct grant for the team grant, and website-testing gains
  its first team block, having had no collaborators block at all

auto_init: true is kept on website-testing even though it only has meaning
at creation: it is in state, and dropping it would show a diff for no
behavioural change. visibility: private likewise restates the module default
and is kept, since it is the fact the access-control design rests on.

Design: docs/superpowers/specs/2026-08-12-ycst-org-uk-migration-design.md
Plan: docs/superpowers/plans/2026-08-13-ycst-org-uk-migration.md (Tasks 5-7)

🤖 Generated with Claude Code

https://claude.ai/code/session_01C15usdmazQC71xZC1YFGHg

[yo61-lastlight]

Renames+relocates the two ycst-* repos' data files under data/ycst-org-uk/ and adds the two moved blocks that carry each repo's four state instances across the provider alias and renamed for_each key. Collaborators switch from a direct PlanetSeth grant to the admins team, which already exists in data/ycst-org-uk/_teams.yaml with planetseth (lowercase) as a member. filename/name: fields, for_each keys, and moved block addresses all line up correctly, and the PR body's own pre-merge sequencing (transfer/rename on GitHub before merging, unscoped plan) is the right call given moved blocks can't be targeted. No issues found.