refactor(electrobun): centralize all shared state into global stores

New stores:
- ui-store.svelte.ts: settingsOpen, paletteOpen, searchOpen, notifDrawerOpen,
  showWizard, settingsCategory, projectToDelete, showAddGroup, newGroupName
- project-tabs-store.svelte.ts: per-project activeTab + activatedTabs via Map

Wired:
- App.svelte: 8 inline $state removed, reads/writes via ui-store
- ProjectCard: activeTab/activatedTabs from project-tabs-store
- SettingsDrawer: activeCategory from ui-store
- CommandPalette: 4 commands call ui-store directly (no CustomEvent dispatch)

Components are now pure view layers reading from stores.

ui-electrobun/src/mainview/App.svelte

@@ -27,17 +27,20 @@
   import {
     getNotifications, clearAll as clearNotifications, getNotifCount,
   } from './notifications-store.svelte.ts';
+  import {
+    getSettingsOpen, setSettingsOpen, toggleSettings,
+    getPaletteOpen, setPaletteOpen, togglePalette,
+    getSearchOpen, toggleSearch,
+    getNotifDrawerOpen, setNotifDrawerOpen, toggleNotifDrawer,
+    getShowWizard, setShowWizard,
+    getProjectToDelete, setProjectToDelete,
+    getShowAddGroup, setShowAddGroup, toggleAddGroup,
+    getNewGroupName, setNewGroupName, resetAddGroupForm,
+    toggleWizard,
+  } from './ui-store.svelte.ts';
 
-  // ── Local UI state (view-only, not domain state) ────────────
+  // ── Local view-only state (not shared across components) ────
   let appReady      = $state(false);
-  let settingsOpen  = $state(false);
-  let paletteOpen   = $state(false);
-  let drawerOpen    = $state(false);
-  let searchOpen    = $state(false);
-  let showWizard    = $state(false);
-  let projectToDelete = $state<string | null>(null);
-  let showAddGroup  = $state(false);
-  let newGroupName  = $state('');
   let sessionStart  = $state(Date.now());
 
   // ── Blink timer ─────────────────────────────────────────────
@@ -81,28 +84,28 @@
   // ── Wizard handler ──────────────────────────────────────────
   function handleWizardCreated(result: WizardResult) {
     addProjectFromWizard(result);
-    showWizard = false;
+    setShowWizard(false);
   }
 
   async function confirmDeleteProject() {
-    if (!projectToDelete) return;
-    await deleteProject(projectToDelete);
-    projectToDelete = null;
+    const toDelete = getProjectToDelete();
+    if (!toDelete) return;
+    await deleteProject(toDelete);
+    setProjectToDelete(null);
   }
 
   // ── Group add (local UI + store) ────────────────────────────
   async function handleAddGroup() {
-    const name = newGroupName.trim();
+    const name = getNewGroupName().trim();
     if (!name) return;
     await wsAddGroup(name);
-    showAddGroup = false;
-    newGroupName = '';
+    resetAddGroupForm();
   }
 
   // ── Notification drawer ─────────────────────────────────────
   function handleClearNotifications() {
     clearNotifications();
-    drawerOpen = false;
+    setNotifDrawerOpen(false);
   }
 
   // ── Toast ref for agent notifications ───────────────────────
@@ -183,8 +186,8 @@
       trackAllProjects();
     });
 
-    keybindingStore.on('palette',  () => { paletteOpen  = !paletteOpen; });
-    keybindingStore.on('settings', () => { settingsOpen = !settingsOpen; });
+    keybindingStore.on('palette',  () => { togglePalette(); });
+    keybindingStore.on('settings', () => { toggleSettings(); });
     keybindingStore.on('group1',   () => setActiveGroup(getGroups()[0]?.id));
     keybindingStore.on('group2',   () => setActiveGroup(getGroups()[1]?.id));
     keybindingStore.on('group3',   () => setActiveGroup(getGroups()[2]?.id));
@@ -194,7 +197,7 @@
     function handleSearchShortcut(e: KeyboardEvent) {
       if (e.ctrlKey && e.shiftKey && e.key === 'F') {
         e.preventDefault();
-        searchOpen = !searchOpen;
+        toggleSearch();
       }
     }
     document.addEventListener('keydown', handleSearchShortcut);
@@ -202,10 +205,10 @@
     function handlePaletteCommand(e: Event) {
       const detail = (e as CustomEvent).detail;
       switch (detail) {
-        case 'settings': settingsOpen = !settingsOpen; break;
-        case 'search': searchOpen = !searchOpen; break;
-        case 'new-project': showWizard = true; break;
-        case 'toggle-sidebar': settingsOpen = !settingsOpen; break;
+        case 'settings': toggleSettings(); break;
+        case 'search': toggleSearch(); break;
+        case 'new-project': setShowWizard(true); break;
+        case 'toggle-sidebar': toggleSettings(); break;
         default: console.log(`[palette] unhandled command: ${detail}`);
       }
     }
@@ -221,15 +224,15 @@
 </script>
 
 <SplashScreen ready={appReady} />
-<SettingsDrawer open={settingsOpen} onClose={() => settingsOpen = false} />
-<CommandPalette open={paletteOpen} onClose={() => paletteOpen = false} />
-<SearchOverlay open={searchOpen} onClose={() => searchOpen = false} />
+<SettingsDrawer open={getSettingsOpen()} onClose={() => setSettingsOpen(false)} />
+<CommandPalette open={getPaletteOpen()} onClose={() => setPaletteOpen(false)} />
+<SearchOverlay open={getSearchOpen()} onClose={() => setSearchOpen(false)} />
 <ToastContainer bind:this={toastRef} />
 <NotifDrawer
-  open={drawerOpen}
+  open={getNotifDrawerOpen()}
   notifications={getNotifications()}
   onClear={handleClearNotifications}
-  onClose={() => drawerOpen = false}
+  onClose={() => setNotifDrawerOpen(false)}
 />
 
 <div
@@ -262,7 +265,7 @@
       <!-- Add group button -->
       <button
         class="group-btn add-group-btn"
-        onclick={() => showAddGroup = !showAddGroup}
+        onclick={() => toggleAddGroup()}
         aria-label="Add group"
         title="Add group"
       >
@@ -270,14 +273,15 @@
       </button>
     </div>
 
-    {#if showAddGroup}
+    {#if getShowAddGroup()}
       <div class="add-group-form">
         <input
           class="add-group-input"
           type="text"
           placeholder="Group name"
-          bind:value={newGroupName}
-          onkeydown={(e) => { if (e.key === 'Enter') handleAddGroup(); if (e.key === 'Escape') showAddGroup = false; }}
+          value={getNewGroupName()}
+          oninput={(e) => setNewGroupName((e.target as HTMLInputElement).value)}
+          onkeydown={(e) => { if (e.key === 'Enter') handleAddGroup(); if (e.key === 'Escape') setShowAddGroup(false); }}
           autofocus
         />
       </div>
@@ -286,7 +290,7 @@
     <!-- Add project button -->
     <button
       class="sidebar-icon"
-      onclick={() => showWizard = !showWizard}
+      onclick={() => toggleWizard()}
       aria-label="Add project"
       title="Add project"
     >
@@ -300,8 +304,8 @@
     <!-- Settings gear -->
     <button
       class="sidebar-icon"
-      class:active={settingsOpen}
-      onclick={() => settingsOpen = !settingsOpen}
+      class:active={getSettingsOpen()}
+      onclick={() => toggleSettings()}
       aria-label="Settings (Ctrl+,)"
       title="Settings (Ctrl+,)"
       data-testid="settings-btn"
@@ -347,9 +351,9 @@
       </div>
 
       <!-- Project wizard overlay (display toggle) -->
-      <div style:display={showWizard ? 'contents' : 'none'}>
+      <div style:display={getShowWizard() ? 'contents' : 'none'}>
         <ProjectWizard
-          onClose={() => showWizard = false}
+          onClose={() => setShowWizard(false)}
           onCreated={handleWizardCreated}
           groupId={getActiveGroupId()}
           groups={getGroups().map(g => ({ id: g.id, name: g.name }))}
@@ -358,11 +362,11 @@
       </div>
 
       <!-- Delete project confirmation -->
-      {#if projectToDelete}
+      {#if getProjectToDelete()}
         <div class="delete-overlay" role="listitem">
-          <p class="delete-text">Delete project "{getProjects().find(p => p.id === projectToDelete)?.name}"?</p>
+          <p class="delete-text">Delete project "{getProjects().find(p => p.id === getProjectToDelete())?.name}"?</p>
           <div class="add-card-actions">
-            <button class="add-cancel" onclick={() => projectToDelete = null}>Cancel</button>
+            <button class="add-cancel" onclick={() => setProjectToDelete(null)}>Cancel</button>
             <button class="delete-confirm" onclick={confirmDeleteProject}>Delete</button>
           </div>
         </div>
@@ -382,8 +386,8 @@
 
     <button
       class="right-icon notif-btn"
-      class:active={drawerOpen}
-      onclick={() => drawerOpen = !drawerOpen}
+      class:active={getNotifDrawerOpen()}
+      onclick={() => toggleNotifDrawer()}
       aria-label="{getNotifCount() > 0 ? `${getNotifCount()} notifications` : 'Notifications'}"
       title="Notifications"
     >