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/20260727140000_pin_function_search_path.sql

@@ -0,0 +1,77 @@
+-- search_path für alle eigenen Funktionen festnageln.
+--
+-- Der Supabase-Linter meldet 34 Funktionen mit „Function Search Path Mutable".
+-- Nachgezählt sind das alles SECURITY-INVOKER-Funktionen; die vier
+-- SECURITY-DEFINER-Funktionen (is_hr_user, current_hr_user_id,
+-- apply_due_pending_changes, fn_track_employee_assignment) setzen den Pfad
+-- längst. Deshalb steht im Advisor auch 0 errors.
+--
+-- Warum das trotzdem behoben wird:
+--
+-- Der Angriff braucht SECURITY DEFINER. Wer in einem Schema, das im
+-- search_path früher liegt, eine eigene Tabelle `employees` anlegt, bringt
+-- eine unqualifiziert schreibende Funktion dazu, auf die untergeschobene
+-- zuzugreifen — mit den Rechten der Eigentümerin der Funktion. Bei INVOKER
+-- läuft alles mit den Rechten der aufrufenden Person, es gibt also nichts zu
+-- gewinnen, und die RLS-Policies greifen unverändert.
+--
+-- Zur Lücke wird die Warnung erst, wenn eine dieser Funktionen später auf
+-- SECURITY DEFINER umgestellt wird, etwa weil eine Mutation an RLS vorbei
+-- schreiben muss. In dem Moment denkt niemand mehr an den search_path.
+-- Einmal festnageln räumt die Falle weg und ändert kein Verhalten.
+--
+-- `pg_temp` steht ausdrücklich am Ende: ohne die Angabe durchsucht Postgres
+-- das temporäre Schema *zuerst*, und dort darf jede Sitzung anlegen, was sie
+-- will.
+
+do $$
+declare
+  v_func record;
+  v_count int := 0;
+begin
+  for v_func in
+    select p.oid::regprocedure as signature
+    from pg_proc p
+    join pg_namespace n on n.oid = p.pronamespace
+    where n.nspname = 'public'
+      -- Nur Funktionen, keine Prozeduren oder Aggregate.
+      and p.prokind = 'f'
+      -- Erweiterungen gehören uns nicht: pg_trgm legt show_trgm und show_limit
+      -- in public ab. Daran zu drehen bricht bei der nächsten Aktualisierung
+      -- der Erweiterung oder wird stillschweigend zurückgesetzt.
+      and not exists (
+        select 1 from pg_depend d where d.objid = p.oid and d.deptype = 'e'
+      )
+      -- Bereits gesetzte nicht anfassen: die vier DEFINER-Funktionen stehen
+      -- auf `search_path = public` und sollen so bleiben.
+      and not exists (
+        select 1 from unnest(coalesce(p.proconfig, '{}')) c where c like 'search_path=%'
+      )
+  loop
+    execute format('alter function %s set search_path = public, pg_temp', v_func.signature);
+    v_count := v_count + 1;
+  end loop;
+
+  raise notice 'search_path festgenagelt für % Funktion(en)', v_count;
+end;
+$$;
+
+-- Gegenprobe: danach darf in public keine eigene Funktion ohne search_path
+-- mehr stehen. Schlägt das an, hat die Schleife oben etwas übersehen — besser
+-- hier, als es im Advisor stehen zu lassen.
+do $$
+declare v_offen int;
+begin
+  select count(*) into v_offen
+  from pg_proc p
+  join pg_namespace n on n.oid = p.pronamespace
+  where n.nspname = 'public'
+    and p.prokind = 'f'
+    and not exists (select 1 from pg_depend d where d.objid = p.oid and d.deptype = 'e')
+    and not exists (select 1 from unnest(coalesce(p.proconfig, '{}')) c where c like 'search_path=%');
+
+  if v_offen > 0 then
+    raise exception 'Es stehen noch % Funktion(en) ohne search_path in public.', v_offen;
+  end if;
+end;
+$$;