refactor(entities): split get_or_create_journal_entity into load + create
Delete `get_or_create_journal_entity` and replace with explicit
`create_journal_entity` alongside the existing reader `load_journal_entity`.
Every caller now composes the two at the call site so writes are visible
in the caller's own source:
load_journal_entity(id) or create_journal_entity(id, ...)
This is the L2 foundation of the entity-write-ownership refactor.
Rewritten call sites:
- think/importers/shared.py (seed_entities)
- apps/speakers/bootstrap.py (bootstrap_voiceprints)
- apps/speakers/discovery.py (identify_cluster — reuses existing load)
- apps/speakers/owner.py (confirm_owner_candidate)
- apps/entities/call.py (attach_entity)
- think/entities/saving.py (_save_entities_attached)