feat(search): Domain-Filter als Dropdown im Suchfeld

Links im großen Suchfeld ein Slider-Icon mit Badge („Alle" oder „2/5"),
das ein Dropdown-Menü mit allen Whitelist-Domains als Checkboxen öffnet.
Auswahl wird per localStorage persistiert und gilt global — Header-Such-
Dropdown konsumiert den gleichen Store und sendet den domains-Parameter
bei jedem Fetch mit.

Leere Menge heißt „alle aktiv", damit neu vom Admin freigeschaltete
Domains automatisch dabei sind. Aktive Auswahl landet als explizite
Intersection mit der Whitelist serverseitig.

- searchLocal nimmt jetzt optional string[] domains → `source_domain IN (…)`.
- searchWeb nimmt jetzt opts.domains → site:-Filter auf die Auswahl
  eingeschränkt. Nicht-Whitelist-Einträge werden ignoriert.
- API-Endpoints: `?domains=a.de,b.de`.
- Neuer Client-Store $lib/client/search-filter.svelte.ts.
- Neue Komponente $lib/components/SearchFilter.svelte (mobile-tauglich,
  44px Touch-Targets, Badge auf engen Screens versteckt).

Home-Seite re-runt die Suche bei Filter-Änderung automatisch (150ms debounce),
ohne dass der User neu tippen muss.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/routes/+layout.svelte

@@ -6,6 +6,7 @@
   import { profileStore } from '$lib/client/profile.svelte';
   import { wishlistStore } from '$lib/client/wishlist.svelte';
   import { pwaStore } from '$lib/client/pwa.svelte';
+  import { searchFilterStore } from '$lib/client/search-filter.svelte';
   import ProfileSwitcher from '$lib/components/ProfileSwitcher.svelte';
   import ConfirmDialog from '$lib/components/ConfirmDialog.svelte';
   import SearchLoader from '$lib/components/SearchLoader.svelte';
@@ -37,6 +38,11 @@
     $page.url.pathname.startsWith('/recipes/') || $page.url.pathname === '/preview'
   );
 
+  function filterParam(): string {
+    const p = searchFilterStore.queryParam;
+    return p ? `&domains=${encodeURIComponent(p)}` : '';
+  }
+
   $effect(() => {
     const q = navQuery.trim();
     if (debounceTimer) clearTimeout(debounceTimer);
@@ -63,7 +69,7 @@
     debounceTimer = setTimeout(async () => {
       try {
         const res = await fetch(
-          `/api/recipes/search?q=${encodeURIComponent(q)}&limit=${NAV_PAGE_SIZE}`
+          `/api/recipes/search?q=${encodeURIComponent(q)}&limit=${NAV_PAGE_SIZE}${filterParam()}`
         );
         const body = await res.json();
         if (navQuery.trim() !== q) return;
@@ -73,7 +79,7 @@
           navWebSearching = true;
           try {
             const wres = await fetch(
-              `/api/recipes/search/web?q=${encodeURIComponent(q)}&pageno=1`
+              `/api/recipes/search/web?q=${encodeURIComponent(q)}&pageno=1${filterParam()}`
             );
             if (navQuery.trim() !== q) return;
             if (!wres.ok) {
@@ -104,7 +110,7 @@
     try {
       if (!navLocalExhausted) {
         const res = await fetch(
-          `/api/recipes/search?q=${encodeURIComponent(q)}&limit=${NAV_PAGE_SIZE}&offset=${navHits.length}`
+          `/api/recipes/search?q=${encodeURIComponent(q)}&limit=${NAV_PAGE_SIZE}&offset=${navHits.length}${filterParam()}`
         );
         const body = await res.json();
         if (navQuery.trim() !== q) return;
@@ -118,7 +124,7 @@
         navWebSearching = navWebHits.length === 0;
         try {
           const wres = await fetch(
-            `/api/recipes/search/web?q=${encodeURIComponent(q)}&pageno=${nextPage}`
+            `/api/recipes/search/web?q=${encodeURIComponent(q)}&pageno=${nextPage}${filterParam()}`
           );
           if (navQuery.trim() !== q) return;
           if (!wres.ok) {
@@ -193,6 +199,7 @@
   onMount(() => {
     profileStore.load();
     void wishlistStore.refresh();
+    void searchFilterStore.load();
     void pwaStore.init();
     document.addEventListener('click', handleClickOutside);
     document.addEventListener('keydown', handleKey);

src/routes/+page.svelte

@@ -7,7 +7,9 @@
   import type { WebHit } from '$lib/server/search/searxng';
   import { randomQuote } from '$lib/quotes';
   import SearchLoader from '$lib/components/SearchLoader.svelte';
+  import SearchFilter from '$lib/components/SearchFilter.svelte';
   import { profileStore } from '$lib/client/profile.svelte';
+  import { searchFilterStore } from '$lib/client/search-filter.svelte';
 
   const LOCAL_PAGE = 30;
 
@@ -26,6 +28,7 @@
   let webExhausted = $state(false);
   let loadingMore = $state(false);
   let skipNextSearch = false;
+  let debounceTimer: ReturnType<typeof setTimeout> | null = null;
 
   type SearchSnapshot = {
     query: string;
@@ -85,6 +88,22 @@
     const urlQ = ($page.url.searchParams.get('q') ?? '').trim();
     if (urlQ) query = urlQ;
     void loadRecent();
+    void searchFilterStore.load();
+  });
+
+  // Bei Änderung der Domain-Auswahl: laufende Suche neu ausführen,
+  // damit der User nicht manuell re-tippen muss.
+  $effect(() => {
+    // eslint-disable-next-line @typescript-eslint/no-unused-expressions
+    searchFilterStore.active;
+    const q = query.trim();
+    if (!q || q.length <= 3) return;
+    if (debounceTimer) clearTimeout(debounceTimer);
+    searching = true;
+    webHits = [];
+    webSearching = false;
+    webError = null;
+    debounceTimer = setTimeout(() => void runSearch(q), 150);
   });
 
   // Sync current query back into the URL as ?q=... via replaceState,
@@ -110,7 +129,10 @@
     void loadFavorites(active.id);
   });
 
-  let debounceTimer: ReturnType<typeof setTimeout> | null = null;
+  function filterParam(): string {
+    const p = searchFilterStore.queryParam;
+    return p ? `&domains=${encodeURIComponent(p)}` : '';
+  }
 
   async function runSearch(q: string) {
     localExhausted = false;
@@ -118,7 +140,7 @@
     webExhausted = false;
     try {
       const res = await fetch(
-        `/api/recipes/search?q=${encodeURIComponent(q)}&limit=${LOCAL_PAGE}`
+        `/api/recipes/search?q=${encodeURIComponent(q)}&limit=${LOCAL_PAGE}${filterParam()}`
       );
       const body = await res.json();
       if (query.trim() !== q) return;
@@ -130,7 +152,9 @@
         // damit der User nicht extra auf „+ weitere" klicken muss.
         webSearching = true;
         try {
-          const wres = await fetch(`/api/recipes/search/web?q=${encodeURIComponent(q)}&pageno=1`);
+          const wres = await fetch(
+            `/api/recipes/search/web?q=${encodeURIComponent(q)}&pageno=1${filterParam()}`
+          );
           if (query.trim() !== q) return;
           if (!wres.ok) {
             const err = await wres.json().catch(() => ({}));
@@ -160,7 +184,7 @@
       if (!localExhausted) {
         // Noch mehr lokale Treffer holen.
         const res = await fetch(
-          `/api/recipes/search?q=${encodeURIComponent(q)}&limit=${LOCAL_PAGE}&offset=${hits.length}`
+          `/api/recipes/search?q=${encodeURIComponent(q)}&limit=${LOCAL_PAGE}&offset=${hits.length}${filterParam()}`
         );
         const body = await res.json();
         if (query.trim() !== q) return;
@@ -175,7 +199,7 @@
         webSearching = webHits.length === 0;
         try {
           const wres = await fetch(
-            `/api/recipes/search/web?q=${encodeURIComponent(q)}&pageno=${nextPage}`
+            `/api/recipes/search/web?q=${encodeURIComponent(q)}&pageno=${nextPage}${filterParam()}`
           );
           if (query.trim() !== q) return;
           if (!wres.ok) {
@@ -256,7 +280,8 @@
 <section class="hero">
   <h1>Kochwas</h1>
   <p class="tagline" aria-live="polite">{quote || '\u00a0'}</p>
-  <form onsubmit={submit}>
+  <form class="search-form" onsubmit={submit}>
+    <SearchFilter />
     <input
       type="search"
       bind:value={query}

src/routes/api/recipes/search/+server.ts

@@ -7,9 +7,13 @@ export const GET: RequestHandler = async ({ url }) => {
   const q = url.searchParams.get('q')?.trim() ?? '';
   const limit = Math.min(Number(url.searchParams.get('limit') ?? 30), 100);
   const offset = Math.max(0, Number(url.searchParams.get('offset') ?? 0));
+  const domains = (url.searchParams.get('domains') ?? '')
+    .split(',')
+    .map((d) => d.trim())
+    .filter(Boolean);
   const hits =
     q.length >= 1
-      ? searchLocal(getDb(), q, limit, offset)
+      ? searchLocal(getDb(), q, limit, offset, domains)
       : offset === 0
         ? listRecentRecipes(getDb(), limit)
         : [];

src/routes/api/recipes/search/web/+server.ts

@@ -7,8 +7,12 @@ export const GET: RequestHandler = async ({ url }) => {
   const q = url.searchParams.get('q')?.trim() ?? '';
   if (!q) error(400, { message: 'Missing ?q=' });
   const pageno = Math.max(1, Math.min(10, Number(url.searchParams.get('pageno') ?? 1)));
+  const domains = (url.searchParams.get('domains') ?? '')
+    .split(',')
+    .map((d) => d.trim())
+    .filter(Boolean);
   try {
-    const hits = await searchWeb(getDb(), q, { pageno });
+    const hits = await searchWeb(getDb(), q, { pageno, domains });
     return json({ query: q, pageno, hits });
   } catch (e) {
     error(502, { message: `Web search unavailable: ${(e as Error).message}` });