feat: leads re-enable flow — detect removed leads on scan + Remove/Restore buttons

- QR scanner (single + multi): detect previously-removed leads via IDB enable flag;
  route to 'reenable' state instead of duplicate error; offer Re-activate button
- API fallback: if create fails and no IDB record, search API for disabled tracking
  record by event_exhibit_id + event_badge_id (adds qry_badge_id param to
  search__exhibit_tracking)
- Lead detail page: Replace raw enable checkbox with Remove Lead (two-click confirm,
  navigates back after) and Restore Lead card (shown when enable is falsy)
- Fix flash of disabled records in leads list: filter !enable in both filtered_lead_li
  derived and local IDB fast-path in handle_search_refresh
- eslint.config.js: disable svelte/no-navigation-without-resolve (no base path configured)
- Also includes _random field annotation cleanup (db_events, ae_types), iframe layout
  fixes, badge view tweaks, test updates, and doc updates from prior session

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/routes/events/+layout.svelte

@@ -211,7 +211,7 @@
         text-gray-800 dark:text-gray-200
         "
 >
-    {#if !$ae_sess?.disable_sys_nav}
+    {#if !$ae_sess?.disable_sys_nav && !$ae_loc?.iframe}
         <nav
             bind:clientHeight={nav_y_height}
             class:hidden={yTop > 600}
@@ -263,8 +263,8 @@
 
     <section
         class:iframe={$ae_loc?.iframe}
-        class:pt-0={!!$ae_sess?.disable_sys_nav}
-        class:pt-12={!$ae_sess?.disable_sys_nav && nav_y_height <= 50}
+        class:pt-0={!!$ae_sess?.disable_sys_nav || $ae_loc?.iframe}
+        class:pt-12={!$ae_sess?.disable_sys_nav && nav_y_height > 0 &&  nav_y_height <= 50}
         class:pt-20={!$ae_sess?.disable_sys_nav && nav_y_height > 50 && nav_y_height <= 100}
         class:pt-32={!$ae_sess?.disable_sys_nav && nav_y_height > 100 && nav_y_height <= 150}
         class:pt-40={!$ae_sess?.disable_sys_nav && nav_y_height > 150 && nav_y_height <= 200}