Codex round-3 finding #1 [SILENT]: baselining after end_sse_headers() left a window
where a run completing between header commit and baseline was absorbed into the
baseline + silently lost. Move resume-id parse + fingerprint baseline before
send_response/headers (both side-effect-free: header read + stat-only fingerprint).
Codex round-3 also flagged finding #2 [CORE] (reconciliation terminal-event-at-cutoff
dedup keeps the handler attached to a dead run queue) — NOT addressed here; escalating
to Nathan per Codex-depth diminishing-returns (3rd round into the same SSE seam class).
Co-authored-by: rodboev <rodboev@users.noreply.github.com>