notifications(P4d): form submission submitter + admin alerts

submitForm now enqueues two kinds of notifications, gated per the design:

  - form_submission_received: ONLY when the submitter is authenticated
    (members or public_auth visibility). Recipient is the verified auth
    email (user.email), never the typed body.email. Anonymous public
    submissions skip the confirmation because confirming to a typed
    address is a victim-spam vector.

  - form_submission_admin: one row per member who holds forms.manage in
    the space (mirrors the forms-guard / forms RLS gate). Dedupe by
    (submission, admin) so a replay is a no-op.

Finding all permission holders without N round-trips needs a new SQL
helper. Migration 047 adds members_with_permission(sid, perm): the
inverted, set-returning form of user_has_permission, with the same
current/late status gate (046) and the same admin shortcut +
space_role_permissions / user_effective_roles fallback. Additive,
introduces no new tables or policies; existing callers unchanged.
Mirrored into schema.sql; types/database.ts updated.

renderFormEmail + formDedupeKey live in notifications-logic; 6 new
render/dedupe unit tests cover both types, fallback labels, escaping.

Suite 565, build clean.

types/database.ts

@@ -1674,6 +1674,10 @@ export type Database = {
         Args: { uid: string; sid: string; perm: string }
         Returns: boolean
       }
+      members_with_permission: {
+        Args: { sid: string; perm: string }
+        Returns: { member_id: string }[]
+      }
     }
     Enums: {
       area_lead_status: "active" | "vacant" | "handoff"