fix(electrobun): re-apply ALL reactive cycle fixes after backup restore

All object-creating template calls replaced with $derived locals:
filteredProjects, activeGroup, totalTokens, totalCost, wizardGroups,
wizardExistingNames. getMountedGroupIds removed entirely.

ui-electrobun/src/mainview/App.svelte

@@ -14,7 +14,7 @@
   import { keybindingStore } from "./keybinding-store.svelte.ts";
   import { setAgentToastFn } from "./agent-store.svelte.ts";
   import { appRpc } from "./rpc.ts";
-  import { initI18n, getDir, getLocale } from "./i18n.svelte.ts";
+  import { initI18n } from "./i18n.svelte.ts";
   import {
     getProjects,
     getGroups,
@@ -74,6 +74,8 @@
   let activeGroup = $derived(getActiveGroup());
   let totalTokens = $derived(getTotalTokensDerived());
   let totalCost = $derived(getTotalCostDerived());
+  let wizardGroups = $derived(getGroups().map(g => ({ id: g.id, name: g.name })));
+  let wizardExistingNames = $derived(getProjects().map(p => p.name));
 
   // ── Blink timer (untracked — must not create reactive dependency) ────
   let blinkVisible = $state(true);
@@ -479,8 +481,8 @@
           onClose={() => setShowWizard(false)}
           onCreated={handleWizardCreated}
           groupId={getActiveGroupId()}
-          groups={getGroups().map((g) => ({ id: g.id, name: g.name }))}
-          existingNames={getProjects().map((p) => p.name)}
+          groups={wizardGroups}
+          existingNames={wizardExistingNames}
         />
       </div>