Curator: recover archived skills back to active

Context

The curator never deletes skills — it archives them: skill_lifecycle.state='archived' (+ absorbed_into, archived_at), the package moved into .archive/, and a pre-pass snapshot in curator_backups/. Today there is no recover path: an over-eager consolidation or a wrongly-archived skill cannot be restored without manual file surgery.

Scope

A first-class recover operation that brings an archived rightx-* skill back to active:

• restore the package files from .archive/ (or a curator_backups/ snapshot),
• flip skill_lifecycle back to active, clear archived_at/absorbed_into as appropriate,
• re-establish any cron links that were dropped/redirected on archive (see maintain_cron_links_for_archived).

Operator surface: dashboard (consistent with pin/unpin being the operator surface) rather than CLI.

Why deferred

Out of scope of the curator observability + safety spec (docs/superpowers/specs/2026-06-15-curator-observability-and-safety-design.md) by decision — that spec guarantees archives stay recoverable (archive-not-delete invariant); this issue builds the actual restore.

Start by reading docs/superpowers/specs/2026-06-15-curator-observability-and-safety-design.md and locating the curator archive flow, skill_lifecycle handling, and maintain_cron_links_for_archived. Trace how the dashboard implements pin/unpin as the operator surface. Done means an archived rightx-* skill can be restored from its archive or backup, returned to active state, and have applicable cron links re-established.