feat(search): tag-based page search surface + per-page tags & collections

Add the /search surface (Pages / Chapters / Mangas tabs) backed by
per-user page tags and per-page collections: schema (migration 0023),
backend endpoints for page tags/collections and tagged-page aggregations
(with the OCR text-search param reserved at 501), plus the frontend API
clients, library Page-tags tab, collection page sections, page context
menu / AddTagsSheet, and reader long-press wiring. Includes the
continuous-reader navigation fixes (?page=N handling, chapter-reset
timing, back-button pops history) and tag-normalization hardening
accumulated on the branch.

Bump version 0.60.2 -> 0.62.0.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/routes/+page.svelte

@@ -18,6 +18,7 @@
     import Search from '@lucide/svelte/icons/search';
     import SlidersHorizontal from '@lucide/svelte/icons/sliders-horizontal';
     import ArrowUpDown from '@lucide/svelte/icons/arrow-up-down';
+    import ArrowRight from '@lucide/svelte/icons/arrow-right';
     import Plus from '@lucide/svelte/icons/plus';
 
     const PAGE_SIZE = 50;
@@ -402,7 +403,22 @@
     {/if}
 {/snippet}
 
-<h1>Mangas</h1>
+<div class="heading-row">
+    <h1>Mangas</h1>
+    <!--
+        Secondary entry point into the per-page search at /search,
+        which is headed "Page search". Label matches the destination's
+        title so the two read as one feature. It filters the user's
+        tagged pages and pivots between Pages / Chapters / Mangas;
+        title-search above stays the primary action. The name is also
+        forward-compatible with the planned OCR text search (which
+        searches page content, not just tags).
+    -->
+    <a class="alt-search" href="/search" data-testid="nav-page-search">
+        <span>Page search</span>
+        <ArrowRight size={14} aria-hidden="true" />
+    </a>
+</div>
 
 <form
     onsubmit={onSubmit}
@@ -562,11 +578,38 @@
 {/if}
 
 <style>
+    .heading-row {
+        display: flex;
+        align-items: baseline;
+        justify-content: space-between;
+        gap: var(--space-3);
+        flex-wrap: wrap;
+    }
+
+    .heading-row h1 {
+        margin-bottom: 0;
+    }
+
+    .alt-search {
+        display: inline-flex;
+        align-items: center;
+        gap: 4px;
+        color: var(--text-muted);
+        font-size: var(--font-sm);
+        text-decoration: none;
+        white-space: nowrap;
+    }
+
+    .alt-search:hover {
+        color: var(--primary);
+    }
+
     .controls {
         display: flex;
         flex-direction: column;
         gap: var(--space-3);
         margin-bottom: var(--space-4);
+        margin-top: var(--space-3);
     }
 
     .search-row {