feat: landing analytics goals, daily bar chart, referrer tracking, contact persistence

- Add per-landing analytics goals (view/click) with admin editor toggle
- Add sticky pay button option for mobile landing pages
- Add daily purchases bar chart (created vs paid) to landing stats
- Replace single purchase count with created/paid split in stats summary
- Add referrer tracking to purchases with hostname display in stats
- Add time display to purchase cards alongside date
- Pass user timezone to stats API for correct daily grouping
- Clamp referrer (500 chars) and subid (255 chars) to backend limits
- Persist contact value per-landing-slug in localStorage
- Fire buy_success analytics goal on successful delivery
- Export USER_TIMEZONE from format utils
- Add analytics/stats translations for fa.json and zh.json locales

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/pages/AdminLandingEditor.tsx

@@ -106,6 +106,7 @@ export default function AdminLandingEditor() {
     methods: false,
     gifts: false,
     background: false,
+    analytics: false,
     footer: false,
   });
 
@@ -137,6 +138,13 @@ export default function AdminLandingEditor() {
     enabled: false,
   });
 
+  // Analytics goals state
+  const [analyticsViewEnabled, setAnalyticsViewEnabled] = useState(false);
+  const [analyticsViewGoal, setAnalyticsViewGoal] = useState('landing_view');
+  const [analyticsClickEnabled, setAnalyticsClickEnabled] = useState(false);
+  const [analyticsClickGoal, setAnalyticsClickGoal] = useState('landing_pay');
+  const [stickyPayButton, setStickyPayButton] = useState(false);
+
   // Discount state
   const [discountPercent, setDiscountPercent] = useState<number | null>(null);
   const [discountOverrides, setDiscountOverrides] = useState<Record<string, number>>({});
@@ -267,6 +275,11 @@ export default function AdminLandingEditor() {
       landingData.discount_ends_at ? isoToDatetimeLocal(landingData.discount_ends_at) : '',
     );
     setDiscountBadgeText(toLocaleDict(landingData.discount_badge_text));
+    setAnalyticsViewEnabled(landingData.analytics_view_enabled ?? false);
+    setAnalyticsViewGoal(landingData.analytics_view_goal || 'landing_view');
+    setAnalyticsClickEnabled(landingData.analytics_click_enabled ?? false);
+    setAnalyticsClickGoal(landingData.analytics_click_goal || 'landing_pay');
+    setStickyPayButton(landingData.sticky_pay_button ?? false);
   }, [landingData]);
 
   // Create mutation
@@ -378,6 +391,11 @@ export default function AdminLandingEditor() {
       discount_badge_text:
         discountPercent !== null ? (nonEmptyDict(discountBadgeText) ?? null) : null,
       background_config: backgroundConfig.enabled ? backgroundConfig : null,
+      analytics_view_enabled: analyticsViewEnabled,
+      analytics_view_goal: analyticsViewGoal,
+      analytics_click_enabled: analyticsClickEnabled,
+      analytics_click_goal: analyticsClickGoal,
+      sticky_pay_button: stickyPayButton,
     };
 
     if (isEdit) {
@@ -1079,6 +1097,72 @@ export default function AdminLandingEditor() {
           <BackgroundConfigEditor value={backgroundConfig} onChange={setBackgroundConfig} />
         </Section>
 
+        {/* Analytics Goals Section */}
+        <Section
+          title={t('admin.landings.analytics', 'Analytics')}
+          open={openSections.analytics}
+          onToggle={() => toggleSection('analytics')}
+        >
+          <div className="space-y-4">
+            {/* View Goal */}
+            <div className="flex items-center justify-between gap-4">
+              <div className="flex-1">
+                <label className="mb-1 block text-sm text-dark-400">
+                  {t('admin.landings.viewGoal', 'View goal')}
+                </label>
+                <input
+                  type="text"
+                  value={analyticsViewGoal}
+                  onChange={(e) => setAnalyticsViewGoal(e.target.value)}
+                  disabled={!analyticsViewEnabled}
+                  className="w-full rounded-lg border border-dark-700 bg-dark-800 px-3 py-2 text-sm text-dark-100 outline-none focus:border-accent-500 disabled:opacity-50"
+                  placeholder="landing_view"
+                />
+              </div>
+              <Toggle
+                checked={analyticsViewEnabled}
+                onChange={() => setAnalyticsViewEnabled((v) => !v)}
+              />
+            </div>
+
+            {/* Click Goal */}
+            <div className="flex items-center justify-between gap-4">
+              <div className="flex-1">
+                <label className="mb-1 block text-sm text-dark-400">
+                  {t('admin.landings.clickGoal', 'Payment click goal')}
+                </label>
+                <input
+                  type="text"
+                  value={analyticsClickGoal}
+                  onChange={(e) => setAnalyticsClickGoal(e.target.value)}
+                  disabled={!analyticsClickEnabled}
+                  className="w-full rounded-lg border border-dark-700 bg-dark-800 px-3 py-2 text-sm text-dark-100 outline-none focus:border-accent-500 disabled:opacity-50"
+                  placeholder="landing_pay"
+                />
+              </div>
+              <Toggle
+                checked={analyticsClickEnabled}
+                onChange={() => setAnalyticsClickEnabled((v) => !v)}
+              />
+            </div>
+            {/* Sticky pay button on mobile */}
+            <div className="flex items-center justify-between gap-4 border-t border-dark-800 pt-4">
+              <div>
+                <p className="text-sm text-dark-300">
+                  {t('admin.landings.stickyPayButton', 'Sticky pay button (mobile)')}
+                </p>
+                <p className="text-xs text-dark-500">
+                  {t(
+                    'admin.landings.stickyPayButtonHint',
+                    'Button pinned to bottom of screen on mobile',
+                  )}
+                </p>
+              </div>
+              <Toggle checked={stickyPayButton} onChange={() => setStickyPayButton((v) => !v)} />
+            </div>
+          </div>
+        </Section>
+
         {/* Footer & Custom CSS Section */}
         <Section
           title={t('admin.landings.content')}