Implement exhibitor search constraints and sync telemetry

- Restricted public exhibitor search to Priority (paid) items only.
- Enforced 3-character search minimum for non-trusted users on landing page.
- Implemented real-time sync telemetry (last refresh and countdown) in Manage tab.
- Added auto-refresh logic with configurable intervals.

src/routes/events/[event_id]/(leads)/leads/+page.svelte

@@ -85,17 +85,26 @@
         const current_search_id = ++last_search_id;
         const event_id = params.event_id;
         const remote_first = params.remote_first;
+        const qry_str = params.str;
 
         if (!event_id) return;
 
+        // --- Search Constraint: Min 3 characters for non-trusted users ---
+        if (!$ae_loc.trusted_access && qry_str.length < 3) {
+            if (log_lvl) console.log('🛑 [Trace] Search string too short for public user.');
+            untrack(() => {
+                exhibit_id_li = [];
+                $events_sess.leads.submit_status__search = 'idle';
+            });
+            return;
+        }
+
         if (log_lvl) console.log(`🔎 [Trace] Exhibit Search #${current_search_id}: START (remote=${remote_first}, event=${event_id}, str=${params.str})`);
 
         untrack(() => {
             $events_sess.leads.submit_status__search = 'searching';
         });
 
-        const qry_str = params.str;
-
         // 1. FAST PATH: Local IDB Search
         if (!remote_first) {
             try {
@@ -103,6 +112,9 @@
                     .where('event_id')
                     .equals(event_id)
                     .filter((exhibit) => {
+                        // Priority Filter for Public
+                        if (!$ae_loc.manager_access && !exhibit.priority) return false;
+
                         if (qry_str) {
                             const name = (exhibit.name ?? '').toLowerCase();
                             const code = (exhibit.code ?? '').toLowerCase();
@@ -111,6 +123,9 @@
                                 !code.includes(qry_str)
                             )
                                 return false;
+                        } else if (!$ae_loc.trusted_access) {
+                            // Don't show default results to public if no search string
+                            return false;
                         }
                         return true;
                     })
@@ -178,6 +193,7 @@
                 api_cfg: $ae_api,
                 event_id: event_id,
                 fulltext_search_qry_str: qry_str || null,
+                priority: $ae_loc.manager_access ? 'all' : 'priority',
                 order_by_li,
                 limit: 100
             });