IDAA: guard attend_json.zoom against SWR IDB re-fire crash

The Zoom button onclick initialises attend_json.zoom. However the
background SWR list fetch (load_ae_obj_li__event in +layout.ts) can
overwrite $idaa_slct.event_obj with a fresh IDB record where
attend_json = {} (no zoom key), even if the Zoom button was already
clicked.

Without the guard, the $effect that rebuilds the Zoom full URL and the
template bindings below the Zoom fields access attend_json.zoom.passcode_enc
on an undefined object, throwing a TypeError and crashing the component.

Fix: add `&& $idaa_slct.event_obj.attend_json?.zoom` guard to both the
$effect condition and the {#if} block that renders the Zoom input fields.

src/routes/idaa/(idaa)/recovery_meetings/ae_idaa_comp__event_obj_id_edit_v2.svelte

@@ -643,13 +643,19 @@ Copy and paste link: <a href="${link_base_url}?event_id=${event_do.event_id}">${
         }
     }
 
-    // Rebuild the Zoom full URL whenever Meeting ID, Passcode, Encrypted Passcode, or Domain changes
+    // Rebuild the Zoom full URL whenever Meeting ID, Passcode, Encrypted Passcode, or Domain changes.
+    // IMPORTANT: Guard attend_json.zoom before accessing its sub-properties.
+    // Background SWR re-fires (load_ae_obj_li__event in +layout.ts) can overwrite
+    // $idaa_slct.event_obj with a fresh IDB record where attend_json = {} (no zoom key),
+    // even if the Zoom button was already clicked.  Without the guard, the access to
+    // attend_json.zoom.passcode_enc below throws a TypeError and crashes the component.
     $effect(() => {
         if (
             $idaa_trig == 'update_zoom_full_url' &&
             $idaa_slct.event_obj.attend_url_code &&
             $idaa_slct.event_obj.attend_url_passcode &&
-            $idaa_sess.recovery_meetings.attend_platform === 'Zoom'
+            $idaa_sess.recovery_meetings.attend_platform === 'Zoom' &&
+            $idaa_slct.event_obj.attend_json?.zoom // guard: zoom may be undefined after IDB re-fire
         ) {
             $idaa_trig = null;
 
@@ -1106,8 +1112,12 @@ Copy and paste link: <a href="${link_base_url}?event_id=${event_do.event_id}">${
                     </div>
                 </div>
 
-                <!-- Zoom fields -->
+                <!-- Zoom fields.
-                {#if $idaa_sess.recovery_meetings.attend_platform === 'Zoom'}
+                     Guard attend_json.zoom: the Zoom button onclick initializes it, but a background
+                     SWR IDB re-fire (load_ae_obj_li__event from +layout.ts) can reset attend_json
+                     to {} afterward, leaving attend_json.zoom undefined.  The bind:value bindings
+                     below crash with a TypeError if zoom is undefined — the guard prevents that. -->
+                {#if $idaa_sess.recovery_meetings.attend_platform === 'Zoom' && $idaa_slct.event_obj.attend_json?.zoom}
                     <div class="platform-fields flex flex-row flex-wrap gap-3">
                         <label class="field-label" for="attend_url_code">
                             Zoom Meeting ID <span class="field-required">*</span>