perf(web): idle-defer non-critical (app) init + lazy-load modals

Homepage/workbench TTI was dominated by the layout synchronously booting
event-bridge, streak tracker, LLM queue, memoro watcher, dashboard store,
shared-uload and reminder scheduler before first paint, plus statically
importing 7 modals/toasts/banners that are rarely-to-never visible on
initial render.

- Keep critical path inline: local-store init (manaStore/tag/link),
  unified sync engine + billing, guest-mode setup.
- Move side-effect streams, projection workers and telemetry to
  requestIdleCallback (with setTimeout fallback).
- Dynamically import KeyboardShortcutsModal, OnboardingWizard,
  GuestWelcomeModal, SessionWarning, EncryptionIntroBanner,
  SuggestionToast, NudgeToast. Modals fetch on first demand; toasts
  mount after idle so their transitive deps (automationsStore,
  day-snapshot projection, streaks, crypto gate) don't land in the
  initial chunk.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/mana/apps/web/src/routes/(app)/+layout.svelte

@@ -1,7 +1,7 @@
 <script lang="ts">
 	import { goto } from '$app/navigation';
 	import { page } from '$app/stores';
-	import type { Snippet } from 'svelte';
+	import type { Component, Snippet } from 'svelte';
 	import { onDestroy, setContext } from 'svelte';
 	import { createReminderScheduler } from '@mana/shared-stores';
 	import { todoReminderSource } from '$lib/modules/todo/reminder-source';
@@ -9,12 +9,7 @@
 	import { initTools } from '$lib/data/tools/init';
 	import { startEventBridge, stopEventBridge } from '$lib/triggers/event-bridge';
 	import { startStreakTracker, stopStreakTracker } from '$lib/data/projections/streaks';
-	import KeyboardShortcutsModal from '$lib/components/KeyboardShortcutsModal.svelte';
-	import SessionWarning from '$lib/components/SessionWarning.svelte';
-	import EncryptionIntroBanner from '$lib/components/EncryptionIntroBanner.svelte';
 	import { bottomBarStore } from '$lib/stores/bottom-bar.svelte';
-	import SuggestionToast from '$lib/components/SuggestionToast.svelte';
-	import NudgeToast from '$lib/components/NudgeToast.svelte';
 	import { locale, _ } from 'svelte-i18n';
 	import {
 		PillNavigation,
@@ -37,7 +32,7 @@
 	import type { InputBarAdapter } from '$lib/quick-input/types';
 	import { getAdapterLoader } from '$lib/quick-input/registry';
 	import { createFallbackAdapter } from '$lib/quick-input/fallback-adapter';
-	import { AuthGate, GuestWelcomeModal } from '@mana/shared-auth-ui';
+	import { AuthGate } from '@mana/shared-auth-ui';
 	import { MANA_APPS, hasAppAccess, ACCESS_TIER_LABELS } from '@mana/shared-branding';
 	import type { AccessTier } from '@mana/shared-branding';
 	import { createGuestMode, type GuestMode } from '$lib/stores/guest-mode.svelte';
@@ -78,7 +73,6 @@
 	import { isNavCollapsed as collapsedStore } from '$lib/stores/navigation';
 	import { getPillAppItems } from '@mana/shared-branding';
 	import { onboardingStore } from '$lib/stores/onboarding.svelte';
-	import { OnboardingWizard } from '$lib/components/onboarding';
 	import { STORAGE_KEYS } from '$lib/config/storage-keys';
 	import { SearchRegistry } from '$lib/search/registry';
 	import { registerAllProviders } from '$lib/search/providers';
@@ -89,6 +83,22 @@
 
 	let { children }: { children: Snippet } = $props();
 
+	// ── Idle-defer helper ───────────────────────────────────
+	// Runs work when the browser is idle so first interaction isn't
+	// blocked by non-critical init (telemetry, schedulers, side-effect
+	// streams). Falls back to setTimeout on browsers without
+	// requestIdleCallback.
+	function idle(cb: () => void, timeout = 2000) {
+		if (typeof window === 'undefined') return;
+		const ric = (
+			window as unknown as {
+				requestIdleCallback?: (cb: () => void, opts?: { timeout?: number }) => void;
+			}
+		).requestIdleCallback;
+		if (ric) ric(cb, { timeout });
+		else setTimeout(cb, 0);
+	}
+
 	// ── App switcher ────────────────────────────────────────
 	let appItems = $derived(getPillAppItems('mana', undefined, undefined, authStore.user?.tier));
 
@@ -391,6 +401,63 @@
 	// ── Guest Mode ──────────────────────────────────────────
 	let guestMode = $state<GuestMode | null>(null);
 
+	// ── Lazy-loaded UI (modals, toasts, banners) ────────────
+	// Static imports for these were adding weight to the initial layout
+	// bundle for components that are rarely-to-never visible on first
+	// paint. Each is fetched either on first demand (modals) or shortly
+	// after idle (always-mounted toasts/banners that self-gate).
+	// Permissive prop typing — props are validated at the call site
+	// where {@const} narrows the component back to its concrete type.
+	type AnyComponent = Component<any>;
+	let KeyboardShortcutsModalC = $state<AnyComponent | null>(null);
+	let OnboardingWizardC = $state<AnyComponent | null>(null);
+	let GuestWelcomeModalC = $state<AnyComponent | null>(null);
+	let SessionWarningC = $state<AnyComponent | null>(null);
+	let EncryptionIntroBannerC = $state<AnyComponent | null>(null);
+	let SuggestionToastC = $state<AnyComponent | null>(null);
+	let NudgeToastC = $state<AnyComponent | null>(null);
+
+	// On-demand: only fetch when the user actually opens them.
+	$effect(() => {
+		if (showShortcuts && !KeyboardShortcutsModalC) {
+			import('$lib/components/KeyboardShortcutsModal.svelte').then((m) => {
+				KeyboardShortcutsModalC = m.default;
+			});
+		}
+	});
+	$effect(() => {
+		if (showOnboarding && !OnboardingWizardC) {
+			import('$lib/components/onboarding').then((m) => {
+				OnboardingWizardC = m.OnboardingWizard;
+			});
+		}
+	});
+	$effect(() => {
+		if (guestMode?.showWelcome && !GuestWelcomeModalC) {
+			import('@mana/shared-auth-ui').then((m) => {
+				GuestWelcomeModalC = m.GuestWelcomeModal;
+			});
+		}
+	});
+
+	// Idle-mount: background toasts/banners that self-gate internally.
+	// Deferring the import also defers their transitive deps
+	// (automationsStore, day-snapshot projection, streaks, crypto gate).
+	idle(() => {
+		void import('$lib/components/SuggestionToast.svelte').then((m) => {
+			SuggestionToastC = m.default;
+		});
+		void import('$lib/components/NudgeToast.svelte').then((m) => {
+			NudgeToastC = m.default;
+		});
+		void import('$lib/components/EncryptionIntroBanner.svelte').then((m) => {
+			EncryptionIntroBannerC = m.default;
+		});
+		void import('$lib/components/SessionWarning.svelte').then((m) => {
+			SessionWarningC = m.default;
+		});
+	});
+
 	// ── Onboarding ──────────────────────────────────────────
 	function handleOnboardingComplete() {
 		onboardingStore.complete();
@@ -415,32 +482,34 @@
 		setGuestPromptNavigator((href) => goto(href));
 		if (authStore.isAuthenticated) guestPrompt.clear();
 
-		// Phase A: Auth-independent — guests + authenticated
+		// Phase A (critical): the local-store inits are required before
+		// liveQueries anywhere downstream (TagStrip, module list views)
+		// can return non-empty results. Keep these awaited.
 		await Promise.all([
 			manaStore.initialize(),
 			tagLocalStore.initialize(),
 			linkLocalStore.initialize(),
 		]);
-		initSharedUload();
-		startEventStore();
-		initTools();
-		startEventBridge();
-		startStreakTracker();
-		await dashboardStore.initialize();
 
-		// Start the persistent LLM task queue. Idempotent — safe to call
+		// Phase A-idle: side-effect streams, telemetry, projection workers.
-		// repeatedly. The queue picks up any tasks left in 'pending' state
+		// All idempotent and self-gated; deferring to the next idle frame
-		// from previous sessions (and reclaims orphaned 'running' rows
+		// lets the first paint + interaction land without waiting on
-		// from a crashed session) before going idle. See $lib/llm-queue.ts.
+		// event-bridge wiring or LLM-queue reclaim work.
-		startLlmQueue();
+		idle(() => {
+			initSharedUload();
+			startEventStore();
+			initTools();
+			startEventBridge();
+			startStreakTracker();
+			startLlmQueue();
+			startMemoroLlmWatcher();
+			// dashboardStore only drives /dashboard — safe to defer; other
+			// routes don't read from it on first paint.
+			void dashboardStore.initialize();
+			reminderScheduler.start();
+		});
 
-		// Module-side LLM result watchers. Each subscribes via Dexie
+		// Restore nav collapsed state (cheap, keep inline)
-		// liveQuery to completed task rows tagged for its module and
-		// writes the results back to the module's own collection
-		// (e.g. memoro auto-titles → memo.title). Idempotent.
-		startMemoroLlmWatcher();
-
-		// Restore nav collapsed state
 		if (typeof localStorage !== 'undefined') {
 			const savedCollapsed = localStorage.getItem(STORAGE_KEYS.NAV_COLLAPSED);
 			if (savedCollapsed === 'true') {
@@ -449,10 +518,11 @@
 			}
 		}
 
-		// Phase B: Auth-dependent — sync, settings, onboarding
+		// Phase B (critical): sync for authenticated users. Data delivery
+		// is user-visible via the pending-count badge, so we keep the
+		// sync engine boot on the critical path.
 		if (authStore.isAuthenticated) {
 			setErrorTrackingUser({ id: authStore.user?.id ?? 'unknown', email: authStore.user?.email });
-			trackReturnVisit();
 			await syncBilling.load();
 			const getToken = () => authStore.getValidToken();
 			unifiedSync = createUnifiedSync(SYNC_SERVER_URL, getToken, syncBilling.active);
@@ -486,18 +556,21 @@
 			// value (0 on a fresh tab) until a sync actually runs.
 			refreshPendingCount();
 
-			userSettings.load().catch(() => {});
+			// Phase B-idle: settings, onboarding gating and return-visit
-
+			// telemetry. None of this gates rendering — onboarding shows
-			onboardingStore.load();
+			// via showOnboarding after the store resolves, which is fine
-			if (onboardingStore.shouldShow) {
+			// on a delay.
-				onboardingStore.start();
+			idle(async () => {
-				ManaEvents.onboardingStarted();
+				trackReturnVisit();
-				showOnboarding = true;
+				userSettings.load().catch(() => {});
-			}
+				await onboardingStore.load();
+				if (onboardingStore.shouldShow) {
+					onboardingStore.start();
+					ManaEvents.onboardingStarted();
+					showOnboarding = true;
+				}
+			});
 		}
-
-		// Phase B2: Start reminder scheduler
-		reminderScheduler.start();
 		// IMPORTANT: do NOT call notificationService.requestPermission() here.
 		// Browsers (Chrome/Firefox) require permission requests to come from
 		// a user gesture. Calling it at mount time queues the prompt until
@@ -628,8 +701,9 @@
 	appName="Mana"
 	locale={($locale || 'de') === 'de' ? 'de' : 'en'}
 >
-	<!-- Onboarding Wizard (auth only) -->
+	<!-- Onboarding Wizard (auth only) — loaded on demand -->
-	{#if showOnboarding && authStore.isAuthenticated}
+	{#if showOnboarding && authStore.isAuthenticated && OnboardingWizardC}
+		{@const OnboardingWizard = OnboardingWizardC}
 		<div
 			class="fixed inset-0 z-50 flex items-center justify-center bg-background/95 backdrop-blur-sm"
 		>
@@ -654,10 +728,14 @@
 
 				<!-- One-time encryption intro — sits at the top of the stack so
 				 it can't be obscured by the QuickInputBar / TagStrip / PillNav.
-				 Self-gates on isVaultUnlocked() so guests never see it. -->
+				 Self-gates on isVaultUnlocked() so guests never see it.
-				<div class="bottom-stack-notification">
+				 Lazy-loaded after idle (see $effects above). -->
-					<EncryptionIntroBanner />
+				{#if EncryptionIntroBannerC}
-				</div>
+					{@const EncryptionIntroBanner = EncryptionIntroBannerC}
+					<div class="bottom-stack-notification">
+						<EncryptionIntroBanner />
+					</div>
+				{/if}
 
 				<!-- Sync pause banner — shown when sync was paused due to insufficient credits -->
 				{#if syncBilling.paused}
@@ -694,8 +772,10 @@
 
 				<!-- Session expiry warning (auth only). Self-gates on the
 				 secondsLeft countdown and only renders inside the stack
-				 when actually warning, so the wrapper is no-op otherwise. -->
+				 when actually warning, so the wrapper is no-op otherwise.
-				{#if authStore.isAuthenticated}
+				 Lazy-loaded after idle. -->
+				{#if authStore.isAuthenticated && SessionWarningC}
+					{@const SessionWarning = SessionWarningC}
 					<div class="bottom-stack-notification">
 						<SessionWarning />
 					</div>
@@ -704,16 +784,23 @@
 				<!-- Cross-module automation suggestions. Lives in the (app)
 				 stack because automationsStore is an (app)-only module
 				 and the toast doesn't make sense on auth/landing pages
-				 anyway. Self-gates on visible state. -->
+				 anyway. Self-gates on visible state. Lazy-loaded after idle. -->
-				<div class="bottom-stack-notification">
+				{#if SuggestionToastC}
-					<SuggestionToast />
+					{@const SuggestionToast = SuggestionToastC}
-				</div>
+					<div class="bottom-stack-notification">
+						<SuggestionToast />
+					</div>
+				{/if}
 
 				<!-- Companion Brain pulse nudges — water reminders, streak
-				 warnings, morning summary etc. Self-gates on active nudges. -->
+				 warnings, morning summary etc. Self-gates on active nudges.
-				<div class="bottom-stack-notification">
+				 Lazy-loaded after idle. -->
-					<NudgeToast />
+				{#if NudgeToastC}
-				</div>
+					{@const NudgeToast = NudgeToastC}
+					<div class="bottom-stack-notification">
+						<NudgeToast />
+					</div>
+				{/if}
 
 				<!-- QuickInputBar with inline nav toggle — gated by the "search" pill -->
 				{#if isQuickInputVisible}
@@ -882,8 +969,11 @@
 			 so it doesn't end up obscured by the QuickInputBar like
 			 EncryptionIntroBanner used to be. -->
 
-		<!-- Keyboard shortcuts modal -->
+		<!-- Keyboard shortcuts modal — loaded on first `?` press -->
-		<KeyboardShortcutsModal open={showShortcuts} onclose={() => (showShortcuts = false)} />
+		{#if KeyboardShortcutsModalC}
+			{@const KeyboardShortcutsModal = KeyboardShortcutsModalC}
+			<KeyboardShortcutsModal open={showShortcuts} onclose={() => (showShortcuts = false)} />
+		{/if}
 	</div>
 
 	<!-- Navigation Context Menu -->
@@ -895,8 +985,9 @@
 		onClose={() => navCtxMenu.close()}
 	/>
 
-	<!-- Guest Welcome Modal -->
+	<!-- Guest Welcome Modal — loaded when guest mode activates -->
-	{#if guestMode}
+	{#if guestMode && GuestWelcomeModalC}
+		{@const GuestWelcomeModal = GuestWelcomeModalC}
 		<GuestWelcomeModal
 			appId="mana"
 			visible={guestMode.showWelcome}