feat: universal search modal

- New SearchModal.svelte: full-screen modal with blurred backdrop
  - Live results as you type (300ms debounce, min 2 chars)
  - Local vs Novelfire badge on each result card (cover + title + author +
    genres + chapter count)
  - Local/remote counts shown in result header
  - 'See all in catalogue' shortcut button + footer repeat link
  - Recent searches (localStorage, max 8, per-item remove + clear all)
  - Genre suggestion chips shown when query is empty or no results found
  - Keyboard navigation: ArrowUp/Down to select, Enter to open, Escape to close
  - Body scroll lock while open
- +layout.svelte:
  - Imports SearchModal, adds searchOpen state
  - Search icon button in nav header (hidden on chapter reader pages)
  - Global keyboard shortcut: '/' or Cmd/Ctrl+K opens modal
  - Shortcut ignored when focused in input/textarea or on chapter pages
  - Modal not shown while ListeningMode is open
  - Auto-closes on route change

ui/src/routes/+layout.svelte

@@ -12,6 +12,7 @@
 	import * as m from '$lib/paraglide/messages.js';
 	import { locales, getLocale } from '$lib/paraglide/runtime.js';
 	import ListeningMode from '$lib/components/ListeningMode.svelte';
+	import SearchModal from '$lib/components/SearchModal.svelte';
 	import { fly } from 'svelte/transition';
 
 	let { children, data }: { children: Snippet; data: LayoutData } = $props();
@@ -19,6 +20,15 @@
 	// Mobile nav drawer state
 	let menuOpen = $state(false);
 
+	// Universal search
+	let searchOpen = $state(false);
+
+	// Close search on navigation
+	$effect(() => {
+		void page.url.pathname;
+		searchOpen = false;
+	});
+
 	// Desktop dropdown menus
 	let userMenuOpen = $state(false);
 	let langMenuOpen = $state(false);
@@ -434,6 +444,20 @@
 		</a>
 		{/if}
 			<div class="ml-auto flex items-center gap-2">
+				<!-- Universal search button (hidden on chapter/reader pages) -->
+				{#if !/\/books\/[^/]+\/chapters\//.test(page.url.pathname)}
+					<button
+						type="button"
+						onclick={() => { searchOpen = true; userMenuOpen = false; langMenuOpen = false; themeMenuOpen = false; menuOpen = false; }}
+						title="Search (/ or ⌘K)"
+						aria-label="Search books"
+						class="flex items-center justify-center w-8 h-8 rounded transition-colors text-(--color-muted) hover:text-(--color-text) hover:bg-(--color-surface-2)"
+					>
+						<svg class="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+							<path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M21 21l-6-6m2-5a7 7 0 11-14 0 7 7 0 0114 0z"/>
+						</svg>
+					</button>
+				{/if}
 				<!-- Theme dropdown (desktop) -->
 				<div class="hidden sm:block relative">
 					<button
@@ -961,3 +985,22 @@
 		/>
 	</div>
 {/if}
+
+<!-- Universal search modal — shown from anywhere except focus mode / listening mode -->
+{#if searchOpen && !listeningModeOpen}
+	<SearchModal onclose={() => { searchOpen = false; }} />
+{/if}
+
+<svelte:window onkeydown={(e) => {
+	// Don't intercept when typing in an input/textarea
+	const tag = (e.target as HTMLElement).tagName;
+	if (tag === 'INPUT' || tag === 'TEXTAREA' || (e.target as HTMLElement).isContentEditable) return;
+	// Don't open on chapter reader pages
+	if (/\/books\/[^/]+\/chapters\//.test(page.url.pathname)) return;
+	if (searchOpen) return;
+	// `/` key or Cmd/Ctrl+K
+	if (e.key === '/' || ((e.metaKey || e.ctrlKey) && e.key === 'k')) {
+		e.preventDefault();
+		searchOpen = true;
+	}
+}} />