feat: Google Drive agency sync with auto folder match

Connect marketing@ once, match Drive folders to tenants by name,
list Drive in Activos, and mirror portal uploads to the linked folder.

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

src/lib/agency.ts

@@ -9,6 +9,7 @@ export const INTEGRATION_PROVIDERS = [
   { id: 'clientify', label: 'Clientify', group: 'crm' },
   { id: 'klaviyo', label: 'Klaviyo', group: 'email' },
   { id: 'mailchimp', label: 'Mailchimp', group: 'email' },
+  { id: 'google_drive', label: 'Google Drive', group: 'files' },
 ] as const;
 
 export type IntegrationProviderId =