queen: idle lanes run speculative attempts -- a second bee on the highest-value long-running issue instead of standing idle #9969

Part of the dispatch roadmap epic #9976. Industry reference and the measured gap are below.

Measured 2026-10-17 14:37Z: 32 of 70 lanes idle with no eligible issue. Idle capacity is paid for and wasted. Bee PR lead time since 2026-10-10: p50 1.6 h, p90 49.6 h (115 merged), so a few stragglers dominate the tail.

Industry reference: MapReduce/Spark speculative execution (backup tasks for stragglers; the MapReduce paper reports 44% shorter jobs); agent products (Codex, Devin, SWE-agent best-of-N) run N attempts and keep the one whose tests pass.

User Scenarios

• As the Queen with idle lanes and no eligible issue, I start a second attempt on a running issue that is high value and long-running, on its own branch, and keep whichever attempt passes review first; the other is closed as superseded.
• As the owner, speculation never takes a lane from real work: the moment an eligible issue appears it outranks a speculative attempt.

Requirements

• may_speculate(idle_lanes, eligible_issues, running_minutes, attempts_on_issue, value_rank) -> bool.
• At most one extra attempt per issue; never on an issue with a send-back in progress.
• winner(a_state, b_state) -> u8 and the rule that closes the loser.

Success Criteria

• Tests: no speculation while any eligible issue exists; never a third attempt; the loser is always closed.
• Invariant: speculative lanes <= idle lanes.
• 0 surviving mutants.

Rules for the bee

• Only .t27 is hand-written; the seal is tool-written (t27c seal --save after a fresh release build on the Railway lab). No .py, .rs, .ts, .sh or .yml edits.
• Every rule gets test blocks and at least one invariant; run tri mutate spec on the new file (on the lab) and kill every surviving mutant. The bar is specs/queen/dispatch.t27 in PR test(queen): kill the 39 surviving mutants of specs/queen/dispatch.t27 #9961: 0 survivors, 0 vacuous tests.
• Write the measured numbers that motivate the card into its header comment, as specs/queen/holds.t27 does.
• Wiring into the runtime (gHashTag/trios) is a separate step: it lands as generated code once gen-ts lowers pure function bodies (gen-ts: lower the bodies of pure functions, so a host imports a spec's rule instead of copying it #7871 / PR gen-ts: lower the bodies of pure functions #7872). Do not hand-write TypeScript here.

Boundary

• specs/queen/speculative.t27
• .trinity/seals/queen_QueenSpeculative.json