feat: add fuelLog.receiptScan tier gating with pro minTier (refs #131)

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

backend/src/core/config/tests/feature-tiers.test.ts

@@ -34,6 +34,30 @@ describe('feature-tiers', () => {
       expect(feature.name).toBe('Scan for Maintenance Schedule');
       expect(feature.upgradePrompt).toBeTruthy();
     });
+
+    it('includes fuelLog.receiptScan feature', () => {
+      const feature = FEATURE_TIERS['fuelLog.receiptScan'];
+      expect(feature).toBeDefined();
+      expect(feature.minTier).toBe('pro');
+      expect(feature.name).toBe('Receipt Scan');
+      expect(feature.upgradePrompt).toBeTruthy();
+    });
+  });
+
+  describe('canAccessFeature - fuelLog.receiptScan', () => {
+    const featureKey = 'fuelLog.receiptScan';
+
+    it('denies access for free tier user', () => {
+      expect(canAccessFeature('free', featureKey)).toBe(false);
+    });
+
+    it('allows access for pro tier user', () => {
+      expect(canAccessFeature('pro', featureKey)).toBe(true);
+    });
+
+    it('allows access for enterprise tier user (inherits pro)', () => {
+      expect(canAccessFeature('enterprise', featureKey)).toBe(true);
+    });
   });
 
   describe('getTierLevel', () => {