Address the review findings that blocked collaboration and hardened tenancy:
- Ownership validation and the view/budget/real-estate policies scope by the
active space instead of user_id, so a member can open detail pages and create
or edit data in a shared space (previously 422/403).
- Authorize purely on live space membership, dropping the current_space_id
shortcut, and reset a removed member's pointer to their personal space so no
stale-pointer write window remains.
- Apply automation rules per space, so a multi-space owner's personal-space
rules never categorise a business-space transaction.
- Flush the offline cursor before the rows on space switch to avoid a stale
re-sync. Adds member-access tests.