admin: Superforms + Zod validation, three-address-defaults schema, profiles toast fix

- Add Superforms + Zod 4 for all admin form validation
- Replace address isDefault with three separate boolean defaults (Mailing, Billing, Shipping)
- Update profiles page with three-checkbox address form and toast improvements
- Convert all admin page server actions to pass request directly to crud
- Export superFormErrorsToFieldErrors helper for profiles server actions
- Regenerate Prisma client for new schema fields

AGENTS.md

@@ -14,16 +14,16 @@ Requires `.env` with at least `DATABASE_URL`, `BETTER_AUTH_SECRET`, `BETTER_AUTH
 
 ## Commands
 
-| npm run ...    | What it does |
-|----------------|-------------|
-| `check`        | `svelte-kit sync && svelte-check` (typecheck) |
-| `lint`         | `prettier --check . && eslint .` (order matters) |
-| `format`       | `prettier --write .` |
-| `test`         | `vitest --run` (single run) |
-| `test:unit`    | `vitest` (watch mode) |
-| `migrate -- --name <name>` | Create a Prisma migration |
-| `deploy`       | Apply pending migrations |
-| `build`        | Production build (adapter-node) |
+| npm run ...                | What it does                                     |
+| -------------------------- | ------------------------------------------------ |
+| `check`                    | `svelte-kit sync && svelte-check` (typecheck)    |
+| `lint`                     | `prettier --check . && eslint .` (order matters) |
+| `format`                   | `prettier --write .`                             |
+| `test`                     | `vitest --run` (single run)                      |
+| `test:unit`                | `vitest` (watch mode)                            |
+| `migrate -- --name <name>` | Create a Prisma migration                        |
+| `deploy`                   | Apply pending migrations                         |
+| `build`                    | Production build (adapter-node)                  |
 
 ## Testing quirks