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/components/premium/pro-badge.tsx

@@ -0,0 +1,12 @@
+import { Badge } from "@/components/ui/badge";
+
+/** Small "Pro" indicator for a feature that's locked for the viewer's tier
+ * but unlockable by upgrading (as opposed to a feature disabled for every
+ * tier, which hides instead of showing this). */
+export function ProBadge({ className }: { className?: string }) {
+  return (
+    <Badge variant="secondary" className={`text-[10px] px-1 py-0 leading-4 ${className ?? ""}`}>
+      Pro
+    </Badge>
+  );
+}