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/project-tabs-store.svelte.ts

@@ -0,0 +1,67 @@
+/**
+ * Project tabs store — per-project tab state.
+ *
+ * Tracks which tab is active and which tabs have been activated (PERSISTED-LAZY
+ * pattern) for each project card. This allows cross-component access — e.g.,
+ * StatusBar can show which tab is active, palette commands can switch tabs.
+ */
+
+// ── Types ────────────────────────────────────────────────────────────────
+
+export type ProjectTab =
+  | 'model' | 'docs' | 'context' | 'files'
+  | 'ssh' | 'memory' | 'comms' | 'tasks';
+
+export const ALL_TABS: ProjectTab[] = [
+  'model', 'docs', 'context', 'files', 'ssh', 'memory', 'comms', 'tasks',
+];
+
+interface TabState {
+  activeTab: ProjectTab;
+  activatedTabs: Set<ProjectTab>;
+}
+
+// ── State ────────────────────────────────────────────────────────────────
+
+let _tabs = $state<Map<string, TabState>>(new Map());
+
+// ── Internal helper ──────────────────────────────────────────────────────
+
+function ensureEntry(projectId: string): TabState {
+  let entry = _tabs.get(projectId);
+  if (!entry) {
+    entry = { activeTab: 'model', activatedTabs: new Set(['model']) };
+    _tabs.set(projectId, entry);
+    // Trigger reactivity by reassigning the map
+    _tabs = new Map(_tabs);
+  }
+  return entry;
+}
+
+// ── Getters ──────────────────────────────────────────────────────────────
+
+export function getActiveTab(projectId: string): ProjectTab {
+  return _tabs.get(projectId)?.activeTab ?? 'model';
+}
+
+export function isTabActivated(projectId: string, tab: ProjectTab): boolean {
+  return _tabs.get(projectId)?.activatedTabs.has(tab) ?? (tab === 'model');
+}
+
+// ── Actions ──────────────────────────────────────────────────────────────
+
+export function setActiveTab(projectId: string, tab: ProjectTab): void {
+  const entry = ensureEntry(projectId);
+  entry.activeTab = tab;
+  entry.activatedTabs = new Set([...entry.activatedTabs, tab]);
+  // Trigger reactivity
+  _tabs = new Map(_tabs);
+}
+
+/** Remove tab state when a project is deleted. */
+export function removeProject(projectId: string): void {
+  if (_tabs.has(projectId)) {
+    _tabs.delete(projectId);
+    _tabs = new Map(_tabs);
+  }
+}