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.test.ts

@@ -0,0 +1,101 @@
+import {
+    describe,
+    it,
+    expect,
+    vi,
+    beforeEach,
+    afterEach,
+    type MockInstance
+} from 'vitest';
+import {
+    addPageToCollection,
+    removePageFromCollection,
+    listCollectionPages,
+    getMyCollectionsContainingPage
+} from './page_collections';
+
+function ok(body: unknown, status = 200): Response {
+    return new Response(JSON.stringify(body), {
+        status,
+        headers: { 'content-type': 'application/json' }
+    });
+}
+
+function noContent(): Response {
+    return new Response(null, { status: 204 });
+}
+
+function pageItemFixture(extra: Record<string, unknown> = {}) {
+    return {
+        page_id: 'p1',
+        chapter_id: 'ch1',
+        manga_id: 'm1',
+        page_number: 1,
+        chapter_number: 1,
+        chapter_title: null,
+        manga_title: 'Berserk',
+        storage_key: 'mangas/m1/chapters/ch1/pages/0001.png',
+        added_at: '2026-01-01T00:00:00Z',
+        ...extra
+    };
+}
+
+describe('page_collections api client', () => {
+    let fetchSpy: MockInstance<typeof globalThis.fetch>;
+
+    beforeEach(() => {
+        fetchSpy = vi.spyOn(globalThis, 'fetch');
+    });
+    afterEach(() => {
+        vi.restoreAllMocks();
+    });
+
+    it('listCollectionPages hits the breadcrumb endpoint', async () => {
+        fetchSpy.mockResolvedValueOnce(
+            ok({
+                items: [pageItemFixture()],
+                page: { limit: 50, offset: 0, total: 1 }
+            })
+        );
+        const r = await listCollectionPages('c1');
+        expect(r.items[0].manga_title).toBe('Berserk');
+        const url = fetchSpy.mock.calls[0][0] as string;
+        expect(url).toMatch(/\/v1\/collections\/c1\/pages$/);
+    });
+
+    it('listCollectionPages forwards pagination params', async () => {
+        fetchSpy.mockResolvedValueOnce(
+            ok({ items: [], page: { limit: 10, offset: 20, total: 0 } })
+        );
+        await listCollectionPages('c1', { limit: 10, offset: 20 });
+        const url = fetchSpy.mock.calls[0][0] as string;
+        expect(url).toContain('limit=10');
+        expect(url).toContain('offset=20');
+    });
+
+    it('addPageToCollection POSTs { page_id }', async () => {
+        fetchSpy.mockResolvedValueOnce(ok({}, 201));
+        await addPageToCollection('c1', 'p1');
+        const init = fetchSpy.mock.calls[0][1] as RequestInit;
+        expect(init.method).toBe('POST');
+        expect(JSON.parse(init.body as string)).toEqual({ page_id: 'p1' });
+    });
+
+    it('removePageFromCollection DELETEs with both ids encoded', async () => {
+        fetchSpy.mockResolvedValueOnce(noContent());
+        await removePageFromCollection('c with space', 'p1');
+        const url = fetchSpy.mock.calls[0][0] as string;
+        // Path includes encoded "c with space" + page id.
+        expect(url).toContain('/v1/collections/c%20with%20space/pages/p1');
+        const init = fetchSpy.mock.calls[0][1] as RequestInit;
+        expect(init.method).toBe('DELETE');
+    });
+
+    it('getMyCollectionsContainingPage unwraps `collection_ids`', async () => {
+        fetchSpy.mockResolvedValueOnce(ok({ collection_ids: ['c1', 'c2'] }));
+        const ids = await getMyCollectionsContainingPage('p1');
+        expect(ids).toEqual(['c1', 'c2']);
+        const url = fetchSpy.mock.calls[0][0] as string;
+        expect(url).toMatch(/\/v1\/pages\/p1\/my-collections$/);
+    });
+});