feat: add WordPress, PrestaShop and Shopify connection slots

Per-client CMS/ecommerce channels in the agency hub with URL/API
placeholders; live sync can come later.

Co-authored-by: Cursor <cursoragent@cursor.com>

sql/cms_integrations.sql

@@ -0,0 +1,31 @@
+-- CMS / ecommerce connection slots per tenant
+-- Idempotent.
+
+alter table public.integrations drop constraint if exists integrations_provider_check;
+alter table public.integrations
+  add constraint integrations_provider_check
+  check (provider in (
+    'meta_ads',
+    'google_ads',
+    'ga4',
+    'search_console',
+    'tag_manager',
+    'clientify',
+    'klaviyo',
+    'mailchimp',
+    'google_drive',
+    'wordpress',
+    'prestashop',
+    'shopify'
+  ));
+
+insert into public.integrations (tenant_id, provider, status, label)
+select t.id, p.provider, 'disconnected', p.label
+from public.tenants t
+cross join (
+  values
+    ('wordpress', 'WordPress'),
+    ('prestashop', 'PrestaShop'),
+    ('shopify', 'Shopify')
+) as p(provider, label)
+on conflict (tenant_id, provider) do nothing;