feat(ST-355): add /solo route, cookie helper, product picker, and solo product page

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

app/(app)/products/[id]/solo/page.tsx

@@ -0,0 +1,81 @@
+import { notFound, redirect } from 'next/navigation'
+import { getSession } from '@/lib/auth'
+import { getAccessibleProduct } from '@/lib/product-access'
+import { setLastProductCookie } from '@/lib/cookies'
+import { prisma } from '@/lib/prisma'
+import { SoloBoard } from '@/components/solo/solo-board'
+import { NoActiveSprint } from '@/components/solo/no-active-sprint'
+import type { SoloTask } from '@/components/solo/solo-board'
+
+interface Props {
+  params: Promise<{ id: string }>
+}
+
+export default async function SoloProductPage({ params }: Props) {
+  const { id } = await params
+  const session = await getSession()
+  if (!session.userId) redirect('/login')
+
+  const product = await getAccessibleProduct(id, session.userId)
+  if (!product) notFound()
+
+  await setLastProductCookie(id)
+
+  const sprint = await prisma.sprint.findFirst({
+    where: { product_id: id, status: 'ACTIVE' },
+  })
+
+  if (!sprint) {
+    return (
+      <div className="flex flex-col h-full">
+        <NoActiveSprint productId={id} productName={product.name} />
+      </div>
+    )
+  }
+
+  const [rawTasks, unassignedCount] = await Promise.all([
+    prisma.task.findMany({
+      where: {
+        story: {
+          sprint_id: sprint.id,
+          assignee_id: session.userId,
+        },
+      },
+      include: {
+        story: { select: { id: true, title: true } },
+      },
+      orderBy: [
+        { story: { sort_order: 'asc' } },
+        { priority: 'asc' },
+        { sort_order: 'asc' },
+      ],
+    }),
+    prisma.story.count({
+      where: { sprint_id: sprint.id, assignee_id: null },
+    }),
+  ])
+
+  const tasks: SoloTask[] = rawTasks.map(t => ({
+    id: t.id,
+    title: t.title,
+    description: t.description,
+    implementation_plan: t.implementation_plan,
+    priority: t.priority,
+    sort_order: t.sort_order,
+    status: t.status as SoloTask['status'],
+    story_id: t.story.id,
+    story_title: t.story.title,
+  }))
+
+  return (
+    <SoloBoard
+      productId={id}
+      productName={product.name}
+      sprintGoal={sprint.sprint_goal}
+      tasks={tasks}
+      unassignedCount={unassignedCount}
+      isDemo={session.isDemo ?? false}
+      currentUserId={session.userId}
+    />
+  )
+}

app/(app)/solo/page.tsx

@@ -0,0 +1,26 @@
+import { redirect } from 'next/navigation'
+import { getSession } from '@/lib/auth'
+import { getLastProductCookie } from '@/lib/cookies'
+import { getAccessibleProduct, productAccessFilter } from '@/lib/product-access'
+import { prisma } from '@/lib/prisma'
+import { ProductPicker } from '@/components/solo/product-picker'
+
+export default async function SoloPage() {
+  const session = await getSession()
+  if (!session.userId) redirect('/login')
+
+  const lastProductId = await getLastProductCookie()
+
+  if (lastProductId) {
+    const product = await getAccessibleProduct(lastProductId, session.userId)
+    if (product && !product.archived) redirect(`/products/${lastProductId}/solo`)
+  }
+
+  const products = await prisma.product.findMany({
+    where: { archived: false, ...productAccessFilter(session.userId) },
+    orderBy: { created_at: 'desc' },
+    select: { id: true, name: true, description: true },
+  })
+
+  return <ProductPicker products={products} />
+}