feat: add company management and user-company assignment in admin panel

shop/supabase/migrations/20260624100000_create_companies_table.sql

@@ -0,0 +1,31 @@
+-- Migration: companies table + company_id in users
+
+-- 1. Tabelle companies erstellen
+CREATE TABLE IF NOT EXISTS public.companies (
+  id         UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+  name       TEXT NOT NULL,
+  created_at TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+-- RLS aktivieren
+ALTER TABLE public.companies ENABLE ROW LEVEL SECURITY;
+
+-- Policies
+DROP POLICY IF EXISTS "Admins und Partner lesen Firmen" ON public.companies;
+DROP POLICY IF EXISTS "Service role kann alles" ON public.companies;
+
+CREATE POLICY "Admins und Partner lesen Firmen"
+  ON public.companies FOR SELECT
+  USING (auth.role() = 'authenticated');
+
+CREATE POLICY "Service role kann alles"
+  ON public.companies FOR ALL
+  USING (true)
+  WITH CHECK (true);
+
+-- 2. company_id zu public.users hinzufügen
+ALTER TABLE public.users
+  ADD COLUMN IF NOT EXISTS company_id UUID REFERENCES public.companies(id) ON DELETE SET NULL;
+
+-- Reload Schema Cache
+NOTIFY pgrst, 'reload schema';