E4 forensic (docs/E4_RESULTS_ZH.md): 272 admission rejections triggered
the fallback seeded_router path, but zero /_snapshot/* HTTP calls hit
the workers. Two root causes:
1. _attempt_d_to_p_sync gated on agentic-side `decode_session.opened`.
By the time fallback runs, agentic has already flipped that flag
to False in response to admission rejection. But D-side
SessionAwareCache may still hold the session (release_session is
not called automatically on admission rejection). Removing the
gate; let D respond authoritatively with "session-not-resident"
if it has actually evicted.
2. _attempt_d_to_p_sync logged decisions via logger.info, but
agentic has no root logger handler so those events silently sank.
Switching every branch (entry skip, prepare fail/not-ok, dump
fail/not-ok, finalize fail/not-ok, ok) to write a structural-log
line at outputs/<run>/structural/d-to-p-sync.jsonl. Each line
carries stage, reason, durations, bytes pushed.
The result doc is updated to reflect the honest E4-1 outcome and
the P1 fix list.
Captures the mid-run state of the E4 sweep (35 min in, 41% of trace
served, 0 admission rejections, 0 d_to_p_sync triggers) along with
the interpretation of that observation: under load-floor K=200 + 3D
topology, admission rarely rejects → reseed is rarely needed → D→P
snapshot is a safety net that doesn't fire in the common case.
Includes a fill-in-after-sweep matrix for H1/H2/H3 verdicts and a
follow-up plan (high-pressure variant to force reseed, ablation to
isolate D→P marginal benefit).
