v458 — two agents drill side by side

The live two-agent check on v457 found two shared-message defects that unit tests could not see.

The kickoff still showed the literal training/training-<agent>.txt, so models stopped to work out what <agent> meant instead of using the exact path in their own TRAINING MODE block. It now says "your drill file" and leaves the path to the block.

The automatic Continue listed every agent's position, and the second model read the first model's "pass complete (17/17)" as its own and tried to start at step 17. Each agent's recorded position now lives in its own block, and Continue is generic. Older transcripts that mention training/training.txt are explicitly marked obsolete.

Verified live in a fresh session with two Groq agents: both passed steps 5–9 concurrently, ending training/training-agent-…-ucy5su.txt and training/training-agent-drill-probe.txt at the same 37-byte training / drill 2 passed (exact match) content, written five seconds apart, with the old shared file untouched. Both read 14–15/17 with zero failed attempts when the check ended.

The PHP drill sequence now replays the reported three-line collision against real bytes and pins both the shared file's ambiguity and the per-agent files' success.

JS 41 files / 1,178 assertions, PHP 33/33 (sandbox 155), docs 14/14. VERSION 457 → 458, APP_VERSION 443 → 444.