The freshness window (updated_at >= live process create_time - 2s) had a
P1 boundary hole: a stale failure written by the PREVIOUS process
immediately before a fast restart landed inside the slack and was
aggregated; if that platform was then removed, the new process never
replaces the entry and NAS stays degraded indefinitely.
Replace clock heuristics with persisted writer identity:
- write_runtime_status now stamps every platform entry with the writing
process's (writer_pid, writer_start_time) — the same PID-reuse
fingerprint the liveness checks use, so a recycled PID never
masquerades as the original writer.
- The aggregation ownership filter requires exact equality between an
entry's stamp and the profile's validated live gateway process
(get_runtime_status_running_pid + _get_process_start_time). No slack,
no timestamps. Legacy entries without a stamp fail closed.
- Writer stamps are process recon (same class as the auth-gated
gateway_pid) and are stripped from all /api/status projections, both
active-profile and merged cross-profile entries.
Near-boundary regression test: prior-process entry stamped 100ms before
restart is excluded; recycled-pid-different-fingerprint excluded;
legacy no-stamp excluded; current-process entry kept.
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