Initial implementation: multi-tenant Kanban board (Phase 1)

Complete Phase 1 foundation with working board, column, and card CRUD:
- SvelteKit + TypeScript + Tailwind CSS v4 + adapter-node
- Full Prisma schema with 18 tables (tenants, users, boards, columns, cards, etc.)
- Multi-tenant architecture with hostname-based tenant resolution
- Email/password auth with bcrypt + session cookies
- Board/Column/Card API routes with full CRUD
- Fractional indexing for drag-and-drop ordering
- Board view with svelte-dnd-action for column and card drag-and-drop
- Card modal with inline editing
- Auth pages (login, register)
- Board listing with create form
- RLS policies SQL script for tenant isolation
- Prisma RLS client extensions (forTenant/bypassRLS)
- Permission helpers (canEditBoard, canManageMembers, etc.)
- Socket.IO server setup (dev Vite plugin + production Express server)
- Client-side socket store for real-time updates
- Docker Compose (app + PostgreSQL 16) + multi-stage Dockerfile
- Database seed script (default tenant + admin user)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

prisma/seed.ts

@@ -0,0 +1,61 @@
+import { PrismaClient } from '@prisma/client';
+import bcrypt from 'bcrypt';
+
+const prisma = new PrismaClient();
+
+async function main() {
+	console.log('Seeding database...');
+
+	// Create default tenant
+	const tenant = await prisma.tenant.upsert({
+		where: { slug: 'default' },
+		update: {},
+		create: {
+			name: 'Default Workspace',
+			slug: 'default'
+		}
+	});
+
+	// Map localhost to default tenant
+	const hostnames = ['localhost', '127.0.0.1'];
+	for (const hostname of hostnames) {
+		await prisma.tenantHostname.upsert({
+			where: { hostname },
+			update: {},
+			create: {
+				hostname,
+				tenantId: tenant.id,
+				isPrimary: hostname === 'localhost'
+			}
+		});
+	}
+
+	// Create admin user
+	const passwordHash = await bcrypt.hash('admin123', 12);
+	await prisma.user.upsert({
+		where: { tenantId_email: { tenantId: tenant.id, email: 'admin@example.com' } },
+		update: {},
+		create: {
+			tenantId: tenant.id,
+			email: 'admin@example.com',
+			name: 'Admin',
+			passwordHash,
+			globalRole: 'SITE_ADMIN',
+			tenantRole: 'ADMIN'
+		}
+	});
+
+	console.log('Seed complete.');
+	console.log(`  Tenant: ${tenant.name} (${tenant.id})`);
+	console.log('  Hostnames: localhost, 127.0.0.1');
+	console.log('  Admin: admin@example.com / admin123');
+}
+
+main()
+	.catch((e) => {
+		console.error(e);
+		process.exit(1);
+	})
+	.finally(async () => {
+		await prisma.$disconnect();
+	});