docs(scope): approvers, T2 duration and confirmation, platform approval policy

[0xmanhnv]

Updates the Scope page for the scope-approval changes (RFC-054 amendment, 2026-10-09):

• Pending entries: a pending entry now names who can approve it, and "Remind approvers" sends the request again. An owner with no other approver can approve their own entry with a reason and an authenticator code (openctem #1601).
• T2 entry limit: intrusive (T2) entries have an owner-set maximum of 7, 30 (default), 90 or 365 days, or permanent (openctem #1620).
• "Keep T2" confirmation: long T2 entries are confirmed periodically. An entry that is not confirmed falls back to T1 after 14 days (openctem #1628).
• Platform approval policy: the platform administrator chooses required, owner-decided or disabled (openctem #1634).

Draft until those four PRs are merged.