The stats endpoint JOINs memory_links to memory_units just to filter
by bank_id. With 8.2M+ links per bank this takes 18+ seconds, and
the control plane polls every 10s — perpetually blocking the server.
Add bank_id column directly to memory_links so the query can filter
on ml.bank_id instead of mu.bank_id, letting Postgres push the filter
down before the JOIN.
- Migration: add bank_id TEXT NOT NULL, backfill from memory_units
- All 4 INSERT paths (temporal, semantic, entity, causal) now write bank_id
- Stats query filters on ml.bank_id instead of mu.bank_id
f50cc25dfb