queen: keyed actors, links and call in the actor runtime; bee dispatcher MVP and benchmark (lane 7) #1719

Part of #1712 (item 7).

Problem

The actor runtime (queen-actors.ts) has monitors, supervisors, slices and nodes. It does not run what actors.t27 already specifies about links and exits:

• links and exit signals: links_after_link, on_exit_signal, death_reason, attach_answer;
• call with an alias and a timeout, and the call-cycle refusal: call_outcome, live_alias, call_admit, chain_add;
• demonitor with flush: down_left_after_demonitor;
• the orderly stop: stop_signal, stop_rank.

A double monitor gives one DOWN, because the watchers are a Set; the spec says two. The bee dispatch is still the round's timer loop in queen-tick.ts runRound: one queend choice per call, one bee after another.

What

1. Runtime: links and trap_exit, a call with an alias and a timeout (late replies dropped), demonitor with flush, the orderly stop in reverse start order, and a correct double monitor. All of it goes through the actors card. New files, with four small hooks in queen-actors.ts.
2. Keyed actors per gHashTag/t27 specs/queen/keyed.t27 (t27#8271): get or spawn, idle passivation, an active cap with LRU eviction, directory cleanup on exit, and a held send that starts a stopping key again.
3. MVP: the bee dispatcher as keyed actors, one per issue, behind TRIOS_QUEEN_DISPATCH=actors, off by default.
4. A benchmark against the dispatch loop on the same seeded input. It measures duplicate pickups, throughput, effective vs nominal parallelism, p95 ready to start, and recovery after a crash and after a hang.

No production swap. The actors rule (gHashTag/t27#7851) needs the numbers first.