feat: database schema, RLS policies, and sign-up trigger (#23) (#34)

Co-authored-by: Ona <no-reply@ona.com>

Author: zacharias-ona

.agents/architecture.md

@@ -28,8 +28,7 @@ Vercel → hosting, preview deploys per PR, production deploys on merge
 
 ## Data Model
 
-No database migrations exist yet. The schema below is the planned target model.
-Create migrations in `supabase/migrations/` as features are implemented.
+The foundational schema is implemented in `supabase/migrations/20260415092907_create_schema.sql`.
 See `docs/product-spec.md` → Data Model for the full column-level schema.
 
 ```

src/lib/types.ts

@@ -0,0 +1,58 @@
+// Database entity types matching the Supabase schema.
+
+export type MemberRole = "owner" | "admin" | "member";
+export type InviteRole = "admin" | "member";
+
+export interface Profile {
+  id: string;
+  email: string;
+  display_name: string;
+  avatar_url: string | null;
+  created_at: string;
+}
+
+export interface Workspace {
+  id: string;
+  name: string;
+  slug: string;
+  is_personal: boolean;
+  created_by: string;
+  created_at: string;
+  updated_at: string;
+}
+
+export interface Member {
+  id: string;
+  workspace_id: string;
+  user_id: string;
+  role: MemberRole;
+  invited_by: string | null;
+  invited_at: string | null;
+  joined_at: string | null;
+  created_at: string;
+}
+
+export interface WorkspaceInvite {
+  id: string;
+  workspace_id: string;
+  email: string;
+  role: InviteRole;
+  invited_by: string;
+  token: string;
+  expires_at: string;
+  accepted_at: string | null;
+  created_at: string;
+}
+
+export interface Page {
+  id: string;
+  workspace_id: string;
+  parent_id: string | null;
+  title: string;
+  content: Record<string, unknown> | null;
+  icon: string | null;
+  position: number;
+  created_by: string;
+  created_at: string;
+  updated_at: string;
+}