Feature Policies API + Invitations Policies (#375)

- Added Feature Policy API: a declarative system to enable/disable/modify default behavior in the SaaS kit
- Team invitation policies with pre-checks using the Feature Policy API: Invite Members dialog now shows loading, errors, and clear reasons when invitations are blocked
- Version bump to 2.16.0 and widespread dependency updates (Supabase, React types, react-i18next, etc.).
- Added comprehensive docs for the new policy system and orchestrators.
- Subscription cancellations now trigger immediate invoicing explicitly

packages/features/team-accounts/src/server/services/account-invitations.service.ts

@@ -12,6 +12,10 @@ import type { DeleteInvitationSchema } from '../../schema/delete-invitation.sche
 import type { InviteMembersSchema } from '../../schema/invite-members.schema';
 import type { UpdateInvitationSchema } from '../../schema/update-invitation.schema';
 
+/**
+ *
+ * Create an account invitations service.
+ */
 export function createAccountInvitationsService(
   client: SupabaseClient<Database>,
 ) {

packages/features/team-accounts/src/server/services/account-per-seat-billing.service.ts

@@ -44,7 +44,8 @@ class AccountPerSeatBillingService {
           subscription_items !inner (
             quantity,
             id,
-            type
+            type,
+            variant_id
           )
         `,
       )