fix: remove Cyrillic markers from agent docs (EN-only, keep compat silent)

agents/codex.md

@@ -25,8 +25,7 @@ It writes to job_dir: `status` (ok|stalled|error), `thread_id`, `last.md`
 1. `JOB=$(mktemp -d /tmp/codex-job-XXXXXX)` — remember the path.
 2. Write `$JOB/prompt.md`: transport preamble (below) + the task for codex.
    If the task contains a block between markers `=== TASK FOR CODEX ===` and
-   `=== END TASK ===` (legacy compat: `=== ЗАДАНИЕ ДЛЯ CODEX ===` /
-   `=== КОНЕЦ ЗАДАНИЯ ===` also counts) — only the block content goes into
+   `=== END TASK ===` — only the block content goes into
    prompt.md (don't copy the markers); text outside the block is instructions
    for you, codex never sees it. No markers — the orchestrator's whole task
    VERBATIM (don't retell; exception — replacements from the tools check).