Run the database in a container of our own

Supabase was only ever the host: the application has talked to PostgreSQL
directly through pg/Kysely for a while. So the move is mostly about
supplying what the platform used to supply.

Proved before building anything. All 65 migrations replay onto an empty
database, and the result matches production exactly — 183 columns, 25
policies, 68 indexes, 84 constraints, identical sets, no diff. The only
function missing from the rebuild turned out to matter, see below.

What the platform supplied, deploy/db-init now does:

  - alpenwerk_app, explicitly NOBYPASSRLS. The whole access model is 21
    RLS policies; a role that bypasses them would leave everything
    working while showing too much, and nobody would notice.
  - pgcrypto and pg_trgm. uuid-ossp was available on Supabase but is
    used nowhere — no column default, no function calls uuid_generate_*.
  - anon, authenticated and service_role as NOLOGIN placeholders. No
    policy names them; they only carry grants the platform handed out,
    and a data dump referencing them would fail to restore without them.
  - A stub `auth` schema. The end state needs none of it — checked: no
    foreign key, no policy, no column default refers to it. The June
    2026 migrations do, and rewriting those would be falsifying history;
    they describe what was true then.

The gap the comparison found: rls_auto_enable() and the ensure_rls event
trigger existed only in the running database, created by hand, in no
migration. That is the net which forces RLS on every newly created
table — the reason a forgotten policy yields an empty table instead of
an open one. A rebuild from migrations would silently not have had it:
everything works, and the next new table is unprotected. Now a migration
(20260819100000), verified by creating a table on the rebuild and
confirming RLS came on by itself.

Data moves separately, via scripts/umzug-von-supabase.sh: schema from
the migrations, then pg_dump --data-only --disable-triggers for the rows.
Without --disable-triggers every foreign key trips over load order. RLS
does not interfere — none of the 19 tables uses FORCE ROW LEVEL
SECURITY, so the owner writes through. The dump is deliberately left on
disk afterwards.

psql and node come from two `tools`-profile services rather than being
installed on the host, so the server needs nothing but Docker. The db
service publishes no port at all — reachable only inside the compose
network.

SUPABASE_DB_URL is renamed MIGRATE_DATABASE_URL, since after this it
describes something else entirely; the old name still works so existing
.env files keep running. Both were exercised, as was the error when
neither is set.

The deploy workflow is set to manual-only. Its preconditions were never
met — no secrets, and whether the job container can reach the host's
Docker daemon is untested — and failing on every push teaches people to
ignore red runs. It also needs updating for the new database service
before it could work at all.

Not verified: none of this has run in an actual container. There is no
Docker daemon on this machine. What is verified is the part that
decides whether it can work — the schema, on a real empty database.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.github/workflows/deploy.yml

@@ -10,9 +10,21 @@ name: Deploy
 # Runner mit dem Label `self-hosted`. Das Repository liegt aber ohnehin auf
 # git.elycon.solutions.)
 
+# Nur von Hand auslösbar (Actions → Deploy → „Run workflow").
+#
+# Lief einmal bei jedem Push auf master. Das ist zurückgenommen: die
+# Voraussetzungen dafür sind nicht erfüllt — es sind keine Secrets hinterlegt,
+# und ob der Job-Container den Docker-Dienst des Hosts überhaupt erreicht, ist
+# ungeprüft. Bei jedem Push zu scheitern erzieht dazu, rote Läufe zu
+# übersehen; dann lieber gar nicht starten.
+#
+# Nach dem Umzug auf den eigenen db-Container stimmt hier ausserdem noch
+# nicht alles: die Secrets unten kennen die neuen Werte (POSTGRES_PASSWORD,
+# APP_DB_PASSWORD) nicht, und Migrationen laufen jetzt über den Dienst
+# `migrate` statt über einen eigenen Node-Schritt. Wer das wieder scharf
+# schaltet, muss beides nachziehen.
 on:
-  push:
-    branches: [master]
+  workflow_dispatch:
 
 # Zwei Pushes kurz hintereinander sollen nicht zwei Deploys übereinander
 # fahren. Der laufende wird **nicht** abgebrochen — mitten im `docker compose