docs(deploy): fix init-script path + add stale-volume reset note

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

deploy/README.md

@@ -70,8 +70,13 @@ Change them via `FRONTEND_PORT`/`GATEWAY_PORT`/`MINIO_PORT` in the secret if any
 
 ## First-run notes
 
-- **Migrations** auto-run once via `scripts/init-db.sh` when the Postgres volume is first
-  created. Later schema changes are applied manually with `psql` (the volume persists).
+- **Migrations** auto-run once via `deploy/postgres-initdb/00-init.sh` (mounted as the
+  whole `/docker-entrypoint-initdb.d` directory — a single-file bind mount left a stale
+  empty dir → "Is a directory") when the Postgres volume is first created. Later schema
+  changes are applied manually with `psql` (the volume persists). ⚠️ If a deploy ever
+  ran with a wrong/empty secret, the volume bakes the wrong password + may skip init →
+  `docker rm -f fr2-postgres && docker volume rm flatrender_pgdata` (only while there's
+  no real data) then re-run, so it re-inits with the current password + migrations.
 - **Rendering** — no After Effects node on the server, so `RENDER_DEV_WORKER=false`.
   Disable rendering in **Admin → فارم رندر → موتور رندر** so users see an "unavailable"
   notice instead of jobs that never finish. Point real render nodes at the server later.