feat(open-notebook): Quadlet pair — app + SurrealDB on a private bridge

Two containers, because that is what upstream runs (docker-compose.yml:6,13):
the app image under supervisord, plus SurrealDB. The `v1-latest-single` tag is
not in play — it bundles its own database, is deprecated upstream, and would
give the host a second hidden DB.

Both images are digest-pinned with Pull=never and a documented one-time pull,
the frank-dragoon posture: a Quadlet on :latest re-resolves on the first restart
after an unrelated daemon-reload, and the failure is silent.

Port map paid for by what is already on the host: seerr holds 127.0.0.1:5055
(since 2026-10-14, live `ss -ltn` agrees), so the API leaves on 5056 and the env
file has to set API_URL to match, because the frontend derives the API URL from
the window origin when it is unset. 8502 publishes on 0.0.0.0 — the service
carries its own password and the episode-audio route is unauthenticated. 8000 is
published nowhere, where upstream exposes it on loopback with root credentials.

The app joins dankclaw_default first and the private systemd-open-notebook
second: it reaches the published fleet endpoints through the former
(host.containers.internal, the arrangement Prometheus is proven against) and
finds its database by container name through the latter. Generated --network
flags keep file order, so the tunable file is listed before the host secret file
in both units — podman applies last-match-wins.

No UserMapping: the app runs as root in its namespace (no USER in the Dockerfile)
and writes only paths owned by that root. Exec= carries no database credential —
`exec start --user --pass` puts it in world-readable argv; the image's own
entrypoint passes it on stdin, so only the container env holds it.

dankclaw/open-notebook/quadlet/open-notebook-surrealdb.container

@@ -0,0 +1,84 @@
+# Quadlet unit: open-notebook's SurrealDB (rootless, boot-persistent).
+#
+# Install path on dankclaw: ~/.config/containers/systemd/open-notebook-surrealdb.container
+# Unit name: open-notebook-surrealdb.service (container name: open-notebook-surrealdb)
+#
+# WHAT IT IS. open-notebook's only datastore: notebooks, notes, sources,
+# provider credentials and podcast episodes all live here. The app talks to it
+# over the WebSocket RPC on the private bridge (SURREAL_URL in
+# scripts/open-notebook.env), which is why the container NAME is part of the
+# contract — renaming it breaks the app's database URL, not just this file.
+#
+# IMAGE. `surrealdb/surrealdb:v2` pinned by manifest-list digest, resolved from
+# the registry on 2026-10-18 (that digest is SurrealDB 2.7.0, image built
+# 2026-09-23; `v2` itself is a MOVING tag, so the digest — not the tag — is what
+# makes this reproducible). Upstream open-notebook's own compose file pins the
+# same `v2` tag, and its Dockerfile copies /surreal out of the same image for
+# the retired single-container variant, so v2 is the version this app is built
+# against. Pull=never + the documented pull step (docs: [[Open Notebook]]):
+#
+#   podman pull docker.io/surrealdb/surrealdb:v2@sha256:e5d7387e3727bbe2f7cd6d869e48cd34777272258572ead37c9656b25f745723
+#
+# NO PUBLISHED PORT. 8000 is deliberately not published: the app reaches it by
+# name on systemd-open-notebook, and a published 8000 would put the RPC with
+# the root credentials on every interface (upstream publishes 127.0.0.1:8000
+# "purely for local debugging" — a `podman exec` probe is enough here). The
+# binary binds 0.0.0.0:8000 INSIDE its own namespace via the image's
+# SURREAL_BIND env; without that image default it would bind loopback only and
+# the app could never connect, so no --bind flag belongs here.
+#
+# CREDENTIALS, AND WHY THEY ARE NOT IN THE COMMAND LINE. The `surreal start`
+# CLI reads its options from the environment (`--username` is [env:
+# SURREAL_USER=], `--password` is [env: SURREAL_PASS=] — verified against the
+# pinned image's own `start --help`), so the credentials arrive through the two
+# EnvironmentFile lines and the argv stays clean. Passing `--pass` instead —
+# what upstream's compose does — would put the database password in
+# /proc/<pid>/cmdline, readable by any `ps` on the host. Note the two
+# spellings: the DATABASE reads SURREAL_PASS, the APP reads SURREAL_PASSWORD,
+# and scripts/open-notebook.env declares both because they must hold the same
+# value; the deployer writes that pair when it seeds the host secret file.
+#
+# NO USER= OVERRIDE. The image runs as uid 65532 (Chainguard glibc-dynamic
+# base). With a NAMED volume that works unmodified: podman creates the volume's
+# backing directory owned by the container's user (measured with this digest —
+# the host directory lands on the mapped subuid and the store starts clean),
+# which is exactly why upstream's `user: root` line is not repeated here: that
+# line is commented in upstream as being "required for bind mounts", and this
+# unit has none. The consequence is that the DB files are NOT readable by dank
+# without `podman unshare` — accepted for a datastore nobody edits by hand;
+# episode AUDIO is a host directory for the opposite reason (see the app unit).
+#
+# HEALTH. The base image is distroless: no shell, no curl, no wget, so no
+# CMD-SHELL probe and no wget/curl probe is possible here (same class of unit
+# as loki, whose probe had to move into the image). SurrealDB ships its own
+# probe instead — `surreal is-ready` connects to ws://localhost:8000 by default
+# and needs no credentials — verified against this digest: it prints `OK` and
+# exits 0 while the server is up. Argument-only HealthCmd, like every unit on
+# this host, because the quadlet generator splits it on spaces.
+
+[Unit]
+Description=SurrealDB (open-notebook datastore)
+After=network-online.target
+Wants=network-online.target
+
+[Container]
+ContainerName=open-notebook-surrealdb
+Image=docker.io/surrealdb/surrealdb:v2@sha256:e5d7387e3727bbe2f7cd6d869e48cd34777272258572ead37c9656b25f745723
+Pull=never
+Network=open-notebook.network
+EnvironmentFile=/home/dank/serverAppConfigs/scripts/open-notebook.env
+EnvironmentFile=/home/dank/Containers/open-notebook/env
+Exec=start --log info rocksdb:/mydata/mydatabase.db
+Volume=open-notebook-db:/mydata
+HealthCmd=/surreal is-ready
+HealthInterval=30s
+HealthTimeout=10s
+HealthRetries=3
+HealthStartPeriod=20s
+
+[Service]
+Restart=always
+RestartSec=5
+
+[Install]
+WantedBy=default.target