feat(ST-903): load active product in layout, replace cookie with DB lookup in solo

- layout.tsx: fetch active_product_id, resolve product, clear stale ref server-side
- NavBar: add activeProduct prop (rendering changes in ST-904)
- solo/page.tsx: redirect via user.active_product_id instead of lastProductId cookie
- proxy.ts: remove lastProductId cookie logic
- lib/cookies.ts: deleted (no longer used)

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

app/(app)/layout.tsx

@@ -3,6 +3,7 @@ import { cookies } from 'next/headers'
 import { getIronSession } from 'iron-session'
 import { SessionData, sessionOptions } from '@/lib/session'
 import { prisma } from '@/lib/prisma'
+import { productAccessFilter } from '@/lib/product-access'
 import { NavBar } from '@/components/shared/nav-bar'
 import { MinWidthBanner } from '@/components/shared/min-width-banner'
 import { StatusBar } from '@/components/shared/status-bar'
@@ -18,7 +19,7 @@ export default async function AppLayout({ children }: { children: React.ReactNod
   const [user, userRoles] = await Promise.all([
     prisma.user.findUnique({
       where: { id: session.userId },
-      select: { username: true, email: true },
+      select: { username: true, email: true, active_product_id: true },
     }),
     prisma.userRole.findMany({
       where: { user_id: session.userId },
@@ -31,6 +32,23 @@ export default async function AppLayout({ children }: { children: React.ReactNod
     redirect('/login')
   }
 
+  // Resolve active product — clear stale reference if archived or inaccessible
+  let activeProduct: { id: string; name: string } | null = null
+  if (user.active_product_id) {
+    const product = await prisma.product.findFirst({
+      where: { id: user.active_product_id, archived: false, ...productAccessFilter(session.userId) },
+      select: { id: true, name: true },
+    })
+    if (product) {
+      activeProduct = product
+    } else {
+      await prisma.user.update({
+        where: { id: session.userId },
+        data: { active_product_id: null },
+      })
+    }
+  }
+
   return (
     <div className="h-screen bg-background flex flex-col overflow-hidden">
       <a href="#main-content" className="sr-only focus:not-sr-only focus:fixed focus:top-2 focus:left-2 focus:z-50 focus:px-4 focus:py-2 focus:bg-primary focus:text-primary-foreground focus:rounded-md focus:text-sm">
@@ -42,6 +60,7 @@ export default async function AppLayout({ children }: { children: React.ReactNod
         userId={session.userId}
         username={user.username}
         email={user.email}
+        activeProduct={activeProduct}
       />
       <MinWidthBanner />
       <main id="main-content" className="flex-1 flex flex-col overflow-y-auto min-h-0">

app/(app)/solo/page.tsx

@@ -1,7 +1,6 @@
 import { redirect } from 'next/navigation'
 import { getSession } from '@/lib/auth'
-import { getLastProductCookie } from '@/lib/cookies'
-import { getAccessibleProduct, productAccessFilter } from '@/lib/product-access'
+import { productAccessFilter } from '@/lib/product-access'
 import { prisma } from '@/lib/prisma'
 import { ProductPicker } from '@/components/solo/product-picker'
 
@@ -9,11 +8,17 @@ export default async function SoloPage() {
   const session = await getSession()
   if (!session.userId) redirect('/login')
 
-  const lastProductId = await getLastProductCookie()
+  const user = await prisma.user.findUnique({
+    where: { id: session.userId },
+    select: { active_product_id: true },
+  })
 
-  if (lastProductId) {
-    const product = await getAccessibleProduct(lastProductId, session.userId)
-    if (product && !product.archived) redirect(`/products/${lastProductId}/solo`)
+  if (user?.active_product_id) {
+    const product = await prisma.product.findFirst({
+      where: { id: user.active_product_id, archived: false, ...productAccessFilter(session.userId) },
+      select: { id: true },
+    })
+    if (product) redirect(`/products/${user.active_product_id}/solo`)
   }
 
   const products = await prisma.product.findMany({

components/shared/nav-bar.tsx

@@ -15,9 +15,10 @@ interface NavBarProps {
   userId: string
   username: string
   email: string | null
+  activeProduct: { id: string; name: string } | null
 }
 
-export function NavBar({ isDemo, roles, userId, username, email }: NavBarProps) {
+export function NavBar({ isDemo, roles, userId, username, email, activeProduct: _activeProduct }: NavBarProps) {
   const pathname = usePathname()
   const currentProduct = useProductStore(s => s.currentProduct)
 

lib/cookies.ts

@@ -1,19 +0,0 @@
-import { cookies } from 'next/headers'
-
-const LAST_PRODUCT_COOKIE = 'lastProductId'
-const THIRTY_DAYS_SECONDS = 60 * 60 * 24 * 30
-
-export async function setLastProductCookie(productId: string) {
-  const store = await cookies()
-  store.set(LAST_PRODUCT_COOKIE, productId, {
-    httpOnly: true,
-    sameSite: 'lax',
-    maxAge: THIRTY_DAYS_SECONDS,
-    path: '/',
-  })
-}
-
-export async function getLastProductCookie(): Promise<string | null> {
-  const store = await cookies()
-  return store.get(LAST_PRODUCT_COOKIE)?.value ?? null
-}

proxy.ts

@@ -5,9 +5,6 @@ import { sessionOptions } from '@/lib/session'
 const protectedRoutes = ['/dashboard', '/products', '/todos', '/settings', '/solo']
 const authRoutes = ['/login', '/register']
 
-const SOLO_ROUTE = /^\/products\/([^/]+)\/solo$/
-const THIRTY_DAYS_SECONDS = 60 * 60 * 24 * 30
-
 export function proxy(request: NextRequest) {
   const path = request.nextUrl.pathname
   const isProtected = protectedRoutes.some(r => path.startsWith(r))
@@ -24,20 +21,7 @@ export function proxy(request: NextRequest) {
     return NextResponse.redirect(new URL('/dashboard', request.url))
   }
 
-  const response = NextResponse.next()
-
-  // Remember last visited product for /solo redirect
-  const soloMatch = path.match(SOLO_ROUTE)
-  if (soloMatch) {
-    response.cookies.set('lastProductId', soloMatch[1], {
-      httpOnly: true,
-      sameSite: 'lax',
-      maxAge: THIRTY_DAYS_SECONDS,
-      path: '/',
-    })
-  }
-
-  return response
+  return NextResponse.next()
 }
 
 export const config = {