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/lib/feature-flags.ts

@@ -93,6 +93,15 @@ export async function getFeatureFlagMatrix(): Promise<Record<FeatureKey, Record<
   return matrix;
 }
 
+/** True if a feature is enabled for at least one tier — i.e. it's a real
+ * upgrade path, not shut off entirely. UI uses this to decide whether a
+ * locked feature should still show (with a "Pro" upsell) or hide outright:
+ * showing an upsell for something no tier can ever unlock would be a dead
+ * end, so those hide instead. */
+export function isFeatureAvailableAnyTier(matrix: Record<FeatureKey, Record<Tier, boolean>>, key: FeatureKey): boolean {
+  return TIERS.some((tier) => matrix[key][tier]);
+}
+
 export async function setFeatureFlag(
   featureKey: FeatureKey,
   tier: Tier,