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/lib/api/page_collections.ts

@@ -0,0 +1,68 @@
+import { request, type Page } from './client';
+
+/** Row returned by `GET /v1/collections/:id/pages`. */
+export type CollectionPageItem = {
+    page_id: string;
+    chapter_id: string;
+    manga_id: string;
+    page_number: number;
+    chapter_number: number;
+    chapter_title: string | null;
+    manga_title: string;
+    storage_key: string;
+    added_at: string;
+};
+
+export type CollectionPagesPage = {
+    items: CollectionPageItem[];
+    page: Page;
+};
+
+export type ListOptions = { limit?: number; offset?: number };
+
+export async function listCollectionPages(
+    collectionId: string,
+    opts: ListOptions = {}
+): Promise<CollectionPagesPage> {
+    const params = new URLSearchParams();
+    if (opts.limit != null) params.set('limit', String(opts.limit));
+    if (opts.offset != null) params.set('offset', String(opts.offset));
+    const qs = params.toString();
+    return request<CollectionPagesPage>(
+        `/v1/collections/${encodeURIComponent(collectionId)}/pages${qs ? `?${qs}` : ''}`
+    );
+}
+
+export async function addPageToCollection(
+    collectionId: string,
+    pageId: string
+): Promise<void> {
+    await request<void>(
+        `/v1/collections/${encodeURIComponent(collectionId)}/pages`,
+        {
+            method: 'POST',
+            headers: { 'content-type': 'application/json' },
+            body: JSON.stringify({ page_id: pageId })
+        }
+    );
+}
+
+export async function removePageFromCollection(
+    collectionId: string,
+    pageId: string
+): Promise<void> {
+    await request<void>(
+        `/v1/collections/${encodeURIComponent(collectionId)}/pages/${encodeURIComponent(pageId)}`,
+        { method: 'DELETE' }
+    );
+}
+
+/** Which of the user's collections currently contain this page. */
+export async function getMyCollectionsContainingPage(
+    pageId: string
+): Promise<string[]> {
+    const r = await request<{ collection_ids: string[] }>(
+        `/v1/pages/${encodeURIComponent(pageId)}/my-collections`
+    );
+    return r.collection_ids;
+}