Backlog: PostgreSQL tests of several packages run one package at a time

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

BACKLOG.md

@@ -928,6 +928,9 @@ model in the catalog); no LibreOffice on the dev machine, so the legacy
 Office path is untested beyond its error; the client is unsigned (Gatekeeper
 and SmartScreen warn); Outlook `.msg` is not read; one document over ~60 MiB
 of JSON (a few thousand pages) is refused rather than split.
+PostgreSQL tests of store, router and adminapi share LLMGW_TEST_POSTGRES and
+the store's TRUNCATE each test; run them with `go test -p 1` or one package
+at a time, or a router test loses its rows mid-run.
 
 ### F3. Retrieval on the request path (M)
 - `llmgw.knowledge: [collections]` in the body (stripped before the