Add jury assignment transfer, cap redistribution, and learning hub overhaul

- Add getTransferCandidates/transferAssignments procedures for targeted
  assignment moves between jurors with TOCTOU guards and audit logging
- Add getOverCapPreview/redistributeOverCap for auto-redistributing
  assignments when a juror's cap is lowered below their current load
- Add TransferAssignmentsDialog (2-step: select projects, pick destinations)
- Extend InlineMemberCap with over-cap detection and redistribute banner
- Extend getReassignmentHistory to show ASSIGNMENT_TRANSFER and CAP_REDISTRIBUTE events
- Learning hub: replace ResourceType/CohortLevel enums with accessJson JSONB,
  add coverImageKey, resource detail pages for jury/mentor, shared renderer
- Migration: 20260221200000_learning_hub_overhaul

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/shared/block-editor.tsx

@@ -2,9 +2,9 @@
 
 import { useEffect, useMemo, useState } from 'react'
 import { useCreateBlockNote } from '@blocknote/react'
-import { BlockNoteView } from '@blocknote/mantine'
+import { BlockNoteView } from '@blocknote/shadcn'
 import '@blocknote/core/fonts/inter.css'
-import '@blocknote/mantine/style.css'
+import '@blocknote/shadcn/style.css'
 
 import type { PartialBlock } from '@blocknote/core'