Remove Supabase

The database moved to a container of our own; the platform is gone.
This takes out what was left of it — and, where the leftovers were load
bearing, moves rather than deletes.

Moved, not deleted:

  supabase/migrations/  -> db/migrations/      the schema's source of truth
  supabase/build-org.ts -> scripts/build-org.ts
  lib/supabase/types.ts -> lib/types.ts        52 import sites repointed

The bookkeeping needed care. It lived in `supabase_migrations.schema_migrations`,
and simply renaming the schema would have left the runner facing an empty
table: it would have called all 67 migrations pending and replayed them
against a database that is long since current. So the runner now creates
`migrationen.schema_migrations` and, once, copies the old rows across —
guarded so a second run does nothing and a fresh database skips it entirely.
Only then does migration 20260907100000 drop the old schema.

Deleted: the CLI config, the seed, the historical schema/function dumps
(nothing read them), scripts/umzug-von-supabase.sh (the move is done), and
both Supabase packages plus the CLI. Nothing in the application imported
them — the build now succeeds with no environment variables at all, which
is the proof.

Integration tests: six of them signed in through Supabase Auth and asserted
against the anon key and the service role. That model is gone, so the tests
were not portable — they are deleted. session-context and
employee-status-filter already ran on pg and are untouched; om-reporting is
ported to a direct connection because it guards a real risk (the reporting
line rule exists twice, once in SQL and once in TypeScript).

CI: the integration job started a Supabase stack. It now runs a postgres
service, applies deploy/db-init and every migration to an empty database —
that was the valuable part, and it still holds — then checks that a second
run is a no-op, which is what proves the bookkeeping works.

Docs: security-review.md audited a service-role key, a cookie adapter and
auth.users, none of which exist. Restating findings about removed components
would suggest today's system had been reviewed; it has not. It now records
what was removed and says a fresh review is due. data-model.md was already
marked obsolete and described the pre-OM schema; azure-migration.md was a
plan for a route not taken. Both deleted.

Verified: npm ci, typecheck, lint, 445 tests, build — all clean without the
packages. Integration tests skip cleanly with no database. Migration SQL and
the runner are reviewed but NOT executed: no Docker here, and the old
instance no longer resolves.

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

db/migrations/20260810110000_fix_hire_workdays_default.sql

@@ -0,0 +1,64 @@
+-- Der Vorgabewert für die Arbeitstage in hire_employee greift nie.
+--
+--     coalesce(array(select jsonb_array_elements_text(payload->'work_days'))::text[],
+--              '{Mo,Di,Mi,Do,Fr}')
+--
+-- Fehlt der Schlüssel, liefert die Unterabfrage keine Zeilen, und `array(…)`
+-- macht daraus ein **leeres** Array — nicht NULL. `coalesce` sieht also
+-- keinen fehlenden Wert und lässt `{}` stehen. Die Bedingung
+-- chk_work_days_valid verlangt aber mindestens einen Tag, und die
+-- Einstellung bricht ab.
+--
+-- Sichtbar ist das bisher nicht, weil der Assistent die Arbeitstage immer
+-- mitschickt und ohne sie gar nicht weiterlässt. Es ist eine Falle für jeden
+-- anderen Aufrufer — und ein Vorgabewert, der nichts vorgibt, ist schlimmer
+-- als keiner: er sieht aus, als wäre der Fall bedacht.
+--
+-- `nullif(…, '{}')` macht aus dem leeren Array wieder ein fehlendes.
+
+do $$
+declare
+  v_def text;
+  v_neu text;
+begin
+  select pg_get_functiondef(p.oid) into v_def
+    from pg_proc p
+    join pg_namespace n on n.oid = p.pronamespace
+   where n.nspname = 'public' and p.proname = 'hire_employee'
+   limit 1;
+
+  v_neu := regexp_replace(
+    v_def,
+    'coalesce\(\s*array\(\s*select\s+jsonb_array_elements_text\(payload->''work_days''\)\s*\)\s*::text\[\]\s*,',
+    'coalesce(nullif(array(select jsonb_array_elements_text(payload->''work_days''))::text[], ''{}''),',
+    'g'
+  );
+
+  if v_neu = v_def then
+    raise exception 'Das Muster für die Arbeitstage passte nicht — hire_employee blieb unverändert.';
+  end if;
+
+  execute v_neu;
+end;
+$$;
+
+-- ═══ Gegenprobe ══════════════════════════════════════════════════
+-- Der Ausdruck in beiden Formen, damit die Regel festgehalten ist und nicht
+-- beim nächsten Mal neu entdeckt werden muss.
+do $$
+begin
+  if array(select jsonb_array_elements_text('{}'::jsonb->'work_days')) is null then
+    raise exception 'array() über einen fehlenden Schlüssel liefert null — die Annahme dieser Migration stimmt nicht mehr.';
+  end if;
+
+  if coalesce(nullif(array(select jsonb_array_elements_text('{}'::jsonb->'work_days'))::text[], '{}'), '{Mo,Di,Mi,Do,Fr}')
+     <> '{Mo,Di,Mi,Do,Fr}'::text[] then
+    raise exception 'Der korrigierte Ausdruck liefert nicht die Vorgabe.';
+  end if;
+
+  if coalesce(nullif(array(select jsonb_array_elements_text('{"work_days":["Mo","Di"]}'::jsonb->'work_days'))::text[], '{}'), '{Mo,Di,Mi,Do,Fr}')
+     <> '{Mo,Di}'::text[] then
+    raise exception 'Der korrigierte Ausdruck überschreibt einen mitgegebenen Wert.';
+  end if;
+end;
+$$;