queen: keyed actors hardened - the claim holder is the actor, a supervised admission on a lane board, a call cycle at any slot #1745

Part of #1712. Night loop #1729, item 7: harden the keyed actors and the bee dispatcher MVP that #1723 built (spec gHashTag/t27#8632).

Gaps #1723 reported:

1. The production claim holder is the Queen's process name, not the actor pid that keyed.t27 claim_is_mine requires. Make the holder the actor's pid inside its process boot, without breaking the round's lease renewal. Prove with the two-node benchmark and a pglive test.
2. The admission actor is unsupervised: if it crashes, the lane count is lost. Put it under a supervisor and make its state recoverable after a restart. Test: crash it mid-round, lanes recover, no duplicate starts.
3. The call-cycle check (chain_has/chain_add) only covers slots 0-63, while runtime slots grow monotonically. Catch a cycle among any processes, from a card.

Card: keyed_guard.t27 (new, vendored byte-identical from gHashTag/t27). Behaviour stays behind TRIOS_QUEEN_DISPATCH=actors, except the call-cycle check, which is a pure fix. Benchmarks go to gHashTag/t27#7851.