fix: standardize locked-vs-hidden treatment across all 9 per-tier gated features (v0.79.0)

Rule, applied consistently everywhere via a new isFeatureAvailableAnyTier() helper: if a feature is enabled on at least one tier, it stays visible for locked-out viewers with a small "Pro" badge and opens an upgrade prompt on click; if a feature is disabled on every tier, it hides entirely, since there's no upgrade path to point at.

Covers: recipe variations, meal/drink pairings, nutrition estimation, Markdown export (5 call sites), weekly nutrition, import from URL, import from photo, and the Instacart grocery-delivery menu item. Previously inconsistent — some hid outright, one showed a lock icon overlapping its own icon.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/web/app/(app)/shopping-lists/[id]/page.tsx

@@ -16,7 +16,7 @@ import { getShoppingListAccess, canWriteShoppingList } from "@/lib/shopping-list
 import { ExportMarkdownButton } from "@/components/shared/export-markdown-button";
 import { shoppingListToMarkdown } from "@/lib/markdown/shopping-list";
 import { getMessages, formatMessage } from "@/lib/i18n/server";
-import { getFeatureFlagMatrix, type Tier } from "@/lib/feature-flags";
+import { getFeatureFlagMatrix, isFeatureAvailableAnyTier, type Tier } from "@/lib/feature-flags";
 
 type Params = { params: Promise<{ id: string }> };
 
@@ -40,8 +40,11 @@ export default async function ShoppingListPage({ params }: Params) {
   const canEdit = canWriteShoppingList(access.role);
   const viewerTier = (session.user as { tier?: string }).tier as Tier | undefined ?? "free";
   const featureFlags = await getFeatureFlagMatrix();
-  const canExportMarkdown = featureFlags.markdown_export[viewerTier];
-  const instacartEnabled = process.env["NEXT_PUBLIC_GROCERY_PROVIDER"] === "instacart" && featureFlags.grocery_delivery[viewerTier];
+  const markdownExportLocked = !featureFlags.markdown_export[viewerTier];
+  const markdownExportAvailable = isFeatureAvailableAnyTier(featureFlags, "markdown_export");
+  const instacartProviderConfigured = process.env["NEXT_PUBLIC_GROCERY_PROVIDER"] === "instacart";
+  const instacartLocked = !featureFlags.grocery_delivery[viewerTier];
+  const instacartAvailable = instacartProviderConfigured && isFeatureAvailableAnyTier(featureFlags, "grocery_delivery");
 
   return (
     <div className="space-y-6 max-w-2xl">
@@ -55,7 +58,7 @@ export default async function ShoppingListPage({ params }: Params) {
         </div>
         <TooltipProvider>
         <div className="flex items-center gap-2 overflow-x-auto pb-0.5 [scrollbar-width:none] [-ms-overflow-style:none] [&::-webkit-scrollbar]:hidden">
-          <GroceryExportButton listId={id} instacartEnabled={instacartEnabled} />
+          <GroceryExportButton listId={id} instacartAvailable={instacartAvailable} instacartLocked={instacartLocked} />
           {access.role === "owner" && (
             <ShareShoppingListButton listId={id} initialIsPublic={list.isPublic} initialPublicEditable={list.publicEditable} />
           )}
@@ -67,10 +70,11 @@ export default async function ShoppingListPage({ params }: Params) {
             } />
             <TooltipContent>{m.common.print}</TooltipContent>
           </Tooltip>
-          {canExportMarkdown && (
+          {markdownExportAvailable && (
             <ExportMarkdownButton
               markdown={shoppingListToMarkdown({ name: list.name, items: list.items })}
               filename={list.name}
+              locked={markdownExportLocked}
             />
           )}
           {access.role === "owner" && (