feat(loyalty): refactor analytics into shared template and add merchant stats API

Extract analytics stat cards, points activity, and location breakdown
into a shared partial used by admin, merchant, and store dashboards.
Add merchant stats API endpoint and client-side merchant filter on admin
analytics page. Extend stats schema with new_this_month and
estimated_liability_cents fields.

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

app/modules/loyalty/static/store/js/loyalty-analytics.js

@@ -20,18 +20,34 @@ function storeLoyaltyAnalytics() {
             points_issued_30d: 0,
             points_redeemed_30d: 0,
             transactions_30d: 0,
-            avg_points_per_member: 0
+            avg_points_per_member: 0,
+            estimated_liability_cents: 0,
         },
 
         loading: false,
         error: null,
 
+        get redemptionRate() {
+            if (this.stats.points_issued_30d === 0) return 0;
+            return Math.round((this.stats.points_redeemed_30d / this.stats.points_issued_30d) * 100);
+        },
+
+        get issuedPercentage() {
+            const total = this.stats.points_issued_30d + this.stats.points_redeemed_30d;
+            if (total === 0) return 50;
+            return Math.round((this.stats.points_issued_30d / total) * 100);
+        },
+
+        get redeemedPercentage() {
+            return 100 - this.issuedPercentage;
+        },
+
         async init() {
             loyaltyAnalyticsLog.info('=== LOYALTY ANALYTICS PAGE INITIALIZING ===');
             if (window._loyaltyAnalyticsInitialized) return;
             window._loyaltyAnalyticsInitialized = true;
 
-            // IMPORTANT: Call parent init first to set storeCode from URL
+            // Call parent init to set storeCode from URL
             const parentInit = data().init;
             if (parentInit) {
                 await parentInit.call(this);
@@ -70,7 +86,8 @@ function storeLoyaltyAnalytics() {
                         points_issued_30d: response.points_issued_30d || 0,
                         points_redeemed_30d: response.points_redeemed_30d || 0,
                         transactions_30d: response.transactions_30d || 0,
-                        avg_points_per_member: response.avg_points_per_member || 0
+                        avg_points_per_member: response.avg_points_per_member || 0,
+                        estimated_liability_cents: response.estimated_liability_cents || 0,
                     };
                     loyaltyAnalyticsLog.info('Stats loaded');
                 }
@@ -83,7 +100,8 @@ function storeLoyaltyAnalytics() {
         },
 
         formatNumber(num) {
-            return num == null ? '0' : new Intl.NumberFormat('en-US').format(num);
+            if (num === null || num === undefined) return '0';
+            return new Intl.NumberFormat('en-US').format(num);
         }
     };
 }