feat(mvp): phase 8 - integration, testing & deployment

Fix all build/type/lint errors (zod 3.25 compat wrapper, Svelte 5 fixes),
write 115 unit tests across 10 test files, expand seed script with demo
data, update Docker config with migration on startup.

src/routes/admin/+layout.svelte

@@ -22,7 +22,7 @@
 		<div class="mb-6 flex flex-wrap items-center gap-4 rounded-xl border border-border bg-card p-4 shadow-sm">
 			<span class="text-sm font-semibold text-foreground">Admin Panel</span>
 			<div class="flex gap-1">
-				{#each navItems as item}
+				{#each navItems as item (item.href)}
 					<a
 						href={item.href}
 						class="rounded-lg px-3 py-1.5 text-sm font-medium transition-colors {isActive(item.href)

src/routes/admin/groups/+page.server.ts

@@ -1,6 +1,6 @@
 import type { Actions, PageServerLoad } from './$types.js';
 import { superValidate, setError } from 'sveltekit-superforms';
-import { zod } from 'sveltekit-superforms/adapters';
+import { zod } from '$lib/utils/zod-adapter.js';
 import { fail } from '@sveltejs/kit';
 import { requireAdmin } from '$lib/server/middleware/authorize.js';
 import * as groupService from '$lib/server/services/groupService.js';

src/routes/admin/settings/+page.server.ts

@@ -1,6 +1,6 @@
 import type { Actions, PageServerLoad } from './$types.js';
 import { superValidate, setError } from 'sveltekit-superforms';
-import { zod } from 'sveltekit-superforms/adapters';
+import { zod } from '$lib/utils/zod-adapter.js';
 import { fail } from '@sveltejs/kit';
 import { requireAdmin } from '$lib/server/middleware/authorize.js';
 import { prisma } from '$lib/server/prisma.js';

src/routes/admin/users/+page.server.ts

@@ -1,6 +1,6 @@
 import type { Actions, PageServerLoad } from './$types.js';
 import { superValidate, setError } from 'sveltekit-superforms';
-import { zod } from 'sveltekit-superforms/adapters';
+import { zod } from '$lib/utils/zod-adapter.js';
 import { fail } from '@sveltejs/kit';
 import { requireAdmin } from '$lib/server/middleware/authorize.js';
 import * as userService from '$lib/server/services/userService.js';