feat: add Instagram, Facebook, TikTok and LinkedIn slots

Organic social channels per client in the agency hub, separate from
paid Meta Ads.

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

src/lib/agency.ts

@@ -13,6 +13,10 @@ export const INTEGRATION_PROVIDERS = [
   { id: 'wordpress', label: 'WordPress', group: 'cms' },
   { id: 'prestashop', label: 'PrestaShop', group: 'cms' },
   { id: 'shopify', label: 'Shopify', group: 'cms' },
+  { id: 'instagram', label: 'Instagram', group: 'social' },
+  { id: 'facebook', label: 'Facebook Page', group: 'social' },
+  { id: 'tiktok', label: 'TikTok', group: 'social' },
+  { id: 'linkedin', label: 'LinkedIn', group: 'social' },
 ] as const;
 
 export type IntegrationProviderId =