v7.61.0

Pairs with engine-service-v0.1.131. The engine refuses a change old clients could make (below), so its deploy is armed with conexus and fires when this client tag is pushed. It is RDR-208's R4 release.

Changed

• The engine refuses address_kind: instance in a mailbox tuple (RDR-208 Phase 3, nexus-galkv.24). Writing one now fails with a schema violation; rows already stored with it stay readable, claimable and ackable. mailbox_send never sent it, so normal messaging is unaffected. The mailbox skill's low-level request/ack pattern now uses address_kind: session; a session still on an older plugin that follows the old pattern gets the error until it updates.
• CCE embedding sends up to 12 chunks per Voyage request (nexus-u2mlh). Each chunk is still its own single-chunk document. An index run makes about a twelfth of the calls it did, which removes the edge timeouts a large run hit, and each call now logs its latency.

Fixed

• A replaced channel waiter no longer marks mail as delivered to nobody (nexus-rxuiq). A waiter's parked wait that outlived it could stamp the next row as announced, so no live waiter ever received it. The engine now fences each wait by a waiter token.
• MinerU formulas keep the space after a LaTeX control word (nexus-pwlqq). \alpha A(e) was stored as \alphaA(e), an undefined macro. Re-index affected PDFs to repair existing chunks.