Run the PR165 complex and bit verification concurrently

[chafreaky]

Change and mathematical scope

The selected PR165 verifier runs independent complex and bit child processes sequentially. Run them concurrently by default, with --jobs 1 retaining sequential execution and --jobs 2 explicitly enabling concurrency. The full isolated repository gate passes --jobs 1 to preserve its existing limit on nested workers.

This PR targets the fork's research/paired-cube-plateau-162 branch, which supplies upstream PR165. That package is not on upstream main. Keeping this follow-up on its existing branch avoids duplicating the construction in another upstream PR; merging this PR will update PR165.

Both complete child checks, arithmetic joins, canonical-certificate comparison, source checks and adverse controls remain enabled. The canonical certificate is byte-identical and the conditional bound remains 297136180212477/(5*10^17). The source closure is refreshed for the verifier, documentation and worker tests. No mathematical claims or inherited assumptions change.

On a DGX Spark with Python 3.12, the standalone prototype measured 40.1 s sequential → 22.5 s parallel, averaging two runs per mode in reversed order. This is selected-verifier latency, not a whole-suite speedup.

Prepared by Chafik Boukhalfa with substantial OpenAI Codex assistance. Existing construction credits and CrocSwap#154's isolated-verification attribution remain intact.

Validation

Validated committed tree e90c43372117d86c31b9b654bfbfcb56fc6f3b4d on the Spark (Python 3.12.3):

• Complete read-only verify.py --jobs 1: PASS in 39.6 s; --jobs 2: PASS in 22.5 s. Both retain certificate SHA-256 67158dd99e325e1d77a7b1055d87012dfdc9668fbd5c0533cd1c7247261b3672.
• Both new worker/child-failure tests: PASS on Python 3.12 and 3.14.
• All 14 native verification groups plus the selected package: PASS on identical isolated source snapshots. The selected package was explicitly run with --jobs 1 inside the suite. The tested source bytes match the published commit.
• verify-positive initially lacked the Boost headers installed by CI; with those supplied locally, the complete group passed in a fresh clone of the same snapshot, with unchanged tracked files.
• Updated source closure: 1,695 files. git diff --check: PASS.

The dispatch tests check that both worker budgets run both children and reproduce the frozen certificate; a barrier confirms the two-worker mode actually runs concurrently. Separate adverse cases require failure of either child to reject the aggregate.