feat(admin): vocab curation queue

Summary

Approve / reject / merge interface for the four controlled vocabularies — disciplines, skills, languages, organizations — that members can propose via inline editors on their dossier.

Requirements

• Brainstorming → spec under docs/superpowers/specs/.
• /admin/vocab — unified queue across the four tables, showing pending rows with proposer, proposed-on date, and current usage count.
• Per-table list views: /admin/vocab/disciplines, /admin/vocab/skills, /admin/vocab/languages, /admin/vocab/organizations.
• Detail view per term: accept / reject / merge-into-canonical actions, name + slug edit before approval, audit log inline.
• Merge action mirrors the organization-merge pattern (set merged_into_id, repoint user_x rows, mark merged source as rejected).
• Bulk-approve action for high-confidence batches (e.g., "approve all programming languages added in the last week"), super_admin gate.

Context

Foundation must ship first (#1956). Existing schema already supports status: pending | approved | rejected on every vocab table and merged_into_id on organizations.

Implementation Notes

• Policy: canApproveVocab requires staff+.
• The proposer (suggestedBy) should see status changes on their own dossier next time they load it (already works via dossier loader).
• Merge UX should highlight near-duplicates (normalized-form match) so admins can resolve obvious dupes in one click.

Read the foundation work in #1956 and the organization-merge pattern, then turn the requirements into a spec under docs/superpowers/specs/. Trace the existing vocabulary tables, status fields, dossier loader, and canApproveVocab policy before implementing the /admin/vocab routes and views. Done means the four queues, detail actions, audit visibility, merge behavior, and gated bulk approval work as specified.