Trigger the 3 wave-3 physical-gold scrapers (per-source isolation)

Fans out to tanaka_jp (Japan), fenegosida_np (Nepal), isagha_eg (Egypt) — one route per wave, concurrently via _run_physical_dispatch, same per-source isolation shape as /physical-gold-id and /physical-gold-intl.

Cadence: 15 minutes (see 20260704120000_physical_gold_w3_pg_cron.sql). Dead-man 2x per source = 30 min.

Dark launch: this route has no tier/pricing gating — it exists purely to populate raw_physical_gold ahead of the TIERS_V2 flip (§6b PR-3), same posture as the earlier physical waves.