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

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

components/solo/no-active-sprint.tsx

@@ -0,0 +1,25 @@
+import Link from 'next/link'
+
+interface NoActiveSprintProps {
+  productId: string
+  productName: string
+}
+
+export function NoActiveSprint({ productId, productName }: NoActiveSprintProps) {
+  return (
+    <div className="flex flex-col items-center justify-center h-full gap-4 text-center px-6">
+      <div className="text-4xl text-muted-foreground">🏃</div>
+      <h2 className="text-lg font-medium text-foreground">Geen actieve sprint</h2>
+      <p className="text-sm text-muted-foreground max-w-sm">
+        Er is nog geen actieve sprint voor <span className="font-medium text-foreground">{productName}</span>.
+        Start een sprint in het Sprint Board om hier je taken te zien.
+      </p>
+      <Link
+        href={`/products/${productId}/sprint`}
+        className="text-sm text-primary hover:underline"
+      >
+        Naar Sprint Board →
+      </Link>
+    </div>
+  )
+}

components/solo/product-picker.tsx

@@ -0,0 +1,46 @@
+import Link from 'next/link'
+
+interface Product {
+  id: string
+  name: string
+  description: string | null
+}
+
+interface ProductPickerProps {
+  products: Product[]
+}
+
+export function ProductPicker({ products }: ProductPickerProps) {
+  return (
+    <div className="p-6 max-w-2xl mx-auto w-full">
+      <h1 className="text-xl font-medium text-foreground mb-2">Solo bord</h1>
+      <p className="text-sm text-muted-foreground mb-6">
+        Kies een product om je persoonlijke Kanban-bord te openen.
+      </p>
+
+      {products.length === 0 ? (
+        <div className="text-center py-12">
+          <p className="text-sm text-muted-foreground mb-3">Je hebt nog geen producten.</p>
+          <Link href="/products/new" className="text-sm text-primary hover:underline">
+            + Nieuw product aanmaken
+          </Link>
+        </div>
+      ) : (
+        <div className="grid gap-2">
+          {products.map(product => (
+            <Link
+              key={product.id}
+              href={`/products/${product.id}/solo`}
+              className="flex flex-col gap-0.5 px-4 py-3 rounded-lg border border-border bg-surface-container hover:bg-surface-container-high transition-colors"
+            >
+              <span className="text-sm font-medium text-foreground">{product.name}</span>
+              {product.description && (
+                <span className="text-xs text-muted-foreground line-clamp-1">{product.description}</span>
+              )}
+            </Link>
+          ))}
+        </div>
+      )}
+    </div>
+  )
+}

components/solo/solo-board.tsx

@@ -0,0 +1,32 @@
+'use client'
+
+export interface SoloTask {
+  id: string
+  title: string
+  description: string | null
+  implementation_plan: string | null
+  priority: number
+  sort_order: number
+  status: 'TO_DO' | 'IN_PROGRESS' | 'REVIEW' | 'DONE'
+  story_id: string
+  story_title: string
+}
+
+export interface SoloBoardProps {
+  productId: string
+  productName: string
+  sprintGoal: string
+  tasks: SoloTask[]
+  unassignedCount: number
+  isDemo: boolean
+  currentUserId: string
+}
+
+// Full implementation in ST-356
+export function SoloBoard(_props: SoloBoardProps) {
+  return (
+    <div className="flex items-center justify-center h-full">
+      <p className="text-sm text-muted-foreground">Solo bord wordt geladen in ST-356…</p>
+    </div>
+  )
+}