perf(hydration): implement cache-first site discovery and SWR event loading

- Refactored lookup_site_domain_v3 to be cache-first, unblocking root layout.
- Implemented Stale-While-Revalidate (SWR) pattern for load_ae_obj_id__event.
- Added global hydration overlay and loading spinner to +layout.svelte.
- Updated site domain whitelist to persist critical account/styling metadata in Dexie.
- Refactored root load function to return immediately if cached site data is found.

src/lib/ae_core/ae_core__site.ts

@@ -91,7 +91,7 @@ export async function lookup_site_domain({
     } as any;
 }
 
-// Updated 2026-01-07
+// Updated 2026-01-26 (Cache-First Optimization)
 export async function lookup_site_domain_v3({
     api_cfg,
     fqdn,
@@ -104,12 +104,34 @@ export async function lookup_site_domain_v3({
     log_lvl?: number;
 }): Promise<ae_SiteDomain | null> {
     if (log_lvl) {
-        console.log(`*** lookup_site_domain_v3() *** fqdn=${fqdn}`);
+        console.log(`*** lookup_site_domain_v3() *** fqdn=${fqdn} (Cache-First)`);
     }
 
+    // 1. FAST PATH: Check local cache first
+    let cached = null;
+    try {
+        cached = await db_core.site_domain.where('fqdn').equals(fqdn).first();
+        if (cached) {
+            if (log_lvl) console.log('BOOTSTRAP: Cache hit. Returning cached site domain immediately.');
+            
+            // Trigger background refresh to keep cache fresh, but don't await it
+            _refresh_site_domain_v3_background({ api_cfg, fqdn, view, log_lvl: 0 });
+            
+            return cached as any;
+        }
+    } catch (err) {
+        console.warn('BOOTSTRAP: Cache read failed.', err);
+    }
+
+    // 2. SLOW PATH: Wait for API if cache is empty
+    return await _refresh_site_domain_v3_background({ api_cfg, fqdn, view, log_lvl });
+}
+
+/**
+ * Internal helper to perform the actual API fetch and cache update
+ */
+async function _refresh_site_domain_v3_background({ api_cfg, fqdn, view, log_lvl }: any) {
     try {
-        // CRITICAL: For the unauthenticated Bootstrap lookup, we must NOT send 
-        // any existing auth tokens or account IDs that might be in the global config.
         const guest_api_cfg = { ...api_cfg };
         guest_api_cfg.headers = { ...api_cfg.headers };
         
@@ -134,30 +156,19 @@ export async function lookup_site_domain_v3({
             and: [{ field: 'fqdn', op: 'eq', value: fqdn }]
         };
 
-        if (log_lvl) {
-            console.log(`BOOTSTRAP SEARCH: fqdn=${fqdn}`);
-            console.log(`BOOTSTRAP HEADERS:`, guest_api_cfg.headers);
-            console.log(`BOOTSTRAP QUERY:`, JSON.stringify(search_query));
-        }
-
-        // We use search because we are looking up by a unique field (fqdn) rather than ID.
-        // The backend should return a list, but since FQDN is unique, it will have 1 item.
         const result_li = await api.search_ae_obj_v3({
             api_cfg: guest_api_cfg,
             obj_type: 'site_domain',
             search_query,
-            view, // This view should ideally join with site and account for the root lookup
+            view,
             enabled: 'enabled',
             hidden: 'all',
             limit: 1,
             log_lvl
         });
 
-        if (log_lvl) console.log(`BOOTSTRAP RESULT:`, result_li);
-
         if (result_li && result_li.length > 0) {
             const result = result_li[0];
-            // Standardize and save to cache
             const processed_obj_li = await process_ae_obj__site_domain_props({
                 obj_li: [result],
                 log_lvl
@@ -172,12 +183,9 @@ export async function lookup_site_domain_v3({
             return result;
         }
     } catch (error: any) {
-        console.log('Site domain lookup V3 failed.', error);
+        if (log_lvl) console.log('Site domain refresh V3 failed.', error);
     }
-
-    if (log_lvl) console.log('Attempting to load site domain from local cache (V3 fallback)...');
-    const cached = await db_core.site_domain.where('fqdn').equals(fqdn).first();
-    return (cached as any) || null;
+    return null;
 }
 
 export async function load_ae_obj_id__site({
@@ -661,6 +669,10 @@ const properties_to_save__site_domain = [
     'site_domain_id_random',
     'site_id',
     'site_id_random',
+    'account_id',
+    'account_id_random',
+    'account_code',
+    'account_name',
     'fqdn',
     'access_key',
     'enable',
@@ -671,6 +683,11 @@ const properties_to_save__site_domain = [
     'sort',
     'group',
     'notes',
+    'header_image_path',
+    'style_href',
+    'google_tracking_id',
+    'access_code_kv_json',
+    'cfg_json',
     'created_on',
     'updated_on',
     'tmp_sort_1',