[FE-96] Optimistic updates and consistent React Query cache invalidation

[yusuftomilola]

Overview

lib/query/keys.ts already defines a well-structured key factory — good foundation. What is missing is consistent invalidation on mutation, so stale data lingers after edits.

Tasks

• Extend the key factory to cover transfers, notifications, locations, and inventory as those land.
• Set sensible global defaults (staleTime, retry, refetchOnWindowFocus) in the query provider.
• Add optimistic updates with rollback for high-frequency mutations: status change, assign, mark notification read, add note.
• Invalidate every affected key after a mutation — approving a transfer must refresh the transfer list, the asset detail, the asset history, and dashboard counts.
• Add prefetching on hover for list → detail navigation.
• Document the conventions so contributors follow them.

Acceptance Criteria

• Mutations update the UI immediately and roll back cleanly on error.
• No stale list remains after a create, update, or delete.
• All query keys come from the factory — no inline key arrays.

Notes for Contributors

Comment below to be assigned.