Fix infinite hydration loop and stabilize global store synchronization

- Refactored layouts to derive account data from stable props instead of reactive stores.
- Wrapped store updates in untrack() with deep equality guards to prevent infinite re-renders.
- Resolved duplicate untrack declarations and missing imports across the project.
- Added fetch safeguards to Element_data_store to prevent redundant API calls.
- Standardized hydration patterns to break circular dependencies during initial load.

src/routes/events/[event_id]/+page.svelte

@@ -39,12 +39,16 @@
     import Event_page_menu from './event_page_menu.svelte';
 
     // Quickly save the data passed from the parent(s) to the Svelte stores, localStorage, and other.
-    let ae_acct = $derived(data[$slct.account_id]);
+    // NOTE: Derived from data.account_id (prop) instead of $slct.account_id (store)
+    // to prevent circular dependency loops during hydration.
+    let ae_acct = $derived(data[data.account_id]);
     let event_id = $derived(data.params.event_id);
 
     $effect(() => {
         if (ae_acct) {
-            $events_slct.event_id = ae_acct.slct.event_id;
+            untrack(() => {
+                $events_slct.event_id = ae_acct.slct.event_id;
+            });
         }
     });
 
@@ -74,11 +78,15 @@
 
     // JSON formatted configuration options for an event, and specifically for the presentation management module.
     $effect(() => {
-        if ($lq__event_obj?.mod_pres_mgmt_json) {
-            events_func.sync_config__event_pres_mgmt({
-                pres_mgmt_cfg_remote: $lq__event_obj.mod_pres_mgmt_json,
-                pres_mgmt_cfg_local: $events_loc.pres_mgmt,
-                log_lvl: log_lvl
+        const remote_cfg = $lq__event_obj?.mod_pres_mgmt_json;
+        const local_cfg = $events_loc.pres_mgmt;
+        if (remote_cfg && local_cfg) {
+            untrack(() => {
+                events_func.sync_config__event_pres_mgmt({
+                    pres_mgmt_cfg_remote: remote_cfg,
+                    pres_mgmt_cfg_local: local_cfg,
+                    log_lvl: log_lvl
+                });
             });
         }
     });