feat(search): frontend content search (text + warnings) + manga warning banner

Surfaces the analysis pipeline in the UI:

- api clients: searchPages() + PageSearchItem/ContentWarning types;
  listMangas cwInclude/cwExclude; MangaDetail.content_warnings.
- /search gains a content-search mode: free-text over OCR+scene and
  tri-state content-warning toggles (include/exclude), driven by URL
  params (text, cw_include, cw_exclude) and the new /me/page-search
  endpoint. Tag browsing is preserved when no content filter is active.
- manga detail renders a deduped content-warning banner.

Tests: vitest param serialization (searchPages CSV/text/cw, listMangas
cw); Playwright text-search + cw-toggle flows (route-mocked). svelte-check
+ build clean; full vitest (258) + search e2e (7) green.

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

frontend/src/lib/api/mangas.test.ts

@@ -267,6 +267,14 @@ describe('mangas api client', () => {
         expect(await getSimilarMangas('b1')).toEqual([]);
     });
 
+    it('listMangas serializes content-warning include/exclude filters', async () => {
+        fetchSpy.mockResolvedValueOnce(ok(emptyPage()));
+        await listMangas({ cwInclude: ['gore'], cwExclude: ['sexual', 'nudity'] });
+        const url = fetchSpy.mock.calls[0][0] as string;
+        expect(url).toContain('cw_include=gore');
+        expect(url).toContain('cw_exclude=sexual%2Cnudity');
+    });
+
     it('getManga throws ApiError carrying the envelope code on non-2xx', async () => {
         fetchSpy.mockResolvedValue(envelope(404, 'not_found', 'manga not found'));
         await expect(getManga('missing')).rejects.toMatchObject({