Queen actors: seven improvements from the competitor study (integration branch actors-next) #1712

Seven improvements to the Queen actor runtime, from the competitor study of 2026-10-09: BEAM/OTP, Akka/Orleans, durable execution, actor-based agent frameworks, and testing and observability practice. The owner asked for all seven ("implement all the improvements", translated).

Integration branch: actors-next. Each item lands there as its own PR, with its spec in gHashTag/t27 and its own tests and benchmark. actors-next merges into queen (production) once, with the owner's OK, so the swarm sits through one deploy drain instead of seven.

1. Telemetry and a log of card decisions, replayed against the card in CI.
2. Turns that really stop: AbortSignal into model calls, and a whole process group killed.
3. Reviewer concurrency read from the measured backlog: the vendored reviewer_concurrency, t27#8212.
4. Long waits stored as Postgres rows, so a 90-minute CI wait holds no process and survives a deploy.
5. Seeded deterministic simulation as a CI gate: each seed runs twice and the logs are compared.
6. PgLink fencing and node incarnations: mail is deleted after it is handled, pids are never reused, and a node its peers think is dead stops itself.
7. Keyed actors, links and call, and an MVP plus benchmark for the bee dispatcher. No swap without the numbers.

Base commit on actors-next: the actors and reviewer cards re-vendored from t27 master f21a0b39c. That brings in the file owner (t27#8137) and reviewer concurrency (t27#8212), and every card function is now exported. The api suite fails the same tests as queen; there are no new failures.