New shared package enabling bidirectional links between records across
apps (e.g. todo→calendar, task→file). Each link creates a forward+reverse
pair sharing a pairId for efficient queries from both sides. Stored in
dedicated IndexedDB (manacore-links), synced via mana-sync.
Includes: types, store, mutations, reactive queries, cached display data
resolvers, ManaLinkBadge and ManaLinkList UI components.
Integrates into Todo app as first consumer — link store initialized in
layout, ManaLinkList rendered in TaskEditModal.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>