feat: redesign download UX — batch select, season download, toast feedback

Episode list:
- Added 'Saison complète' header button to download all episodes at once
- Added multi-select mode with checkboxes for batch episode download
- Individual download buttons now show visual feedback (checkmark + reset)
- Better grid/list toggle with selection state indicators

Search results (anime + series):
- Redesigned download dropdown with icons, descriptions, spinner on click
- Smooth scale/opacity transitions on dropdown open/close
- Consistent btn-success color for all download actions

Series search JS:
- Replaced basic <select> with scrollable episode list inline
- Added 'Tout télécharger' button per series card
- Replaced all alert() calls with toast notifications
- Episode buttons show checkmark on successful download

Anime details JS:
- Added batch download button next to episode select
- Fixed pre-existing lint error (escaped quote in translateSynopsis)
- Standardized download icon to fa-arrow-down across all cards

Recommendations + Tabs JS:
- Unified download button color (btn-success) across all card types
- Consistent icon (fa-arrow-down) for download actions

Toast system:
- Connected to existing Alpine.js toast infrastructure (show-toast events)

static/js/anime-details.js

@@ -274,8 +274,8 @@ function renderAnimeDetails(anime) {
                         <a href="${escapeHtml(anime.url)}" target="_blank" class="btn btn-secondary btn-sm">
                             <i class="fa-solid fa-link"></i> Voir sur MAL
                         </a>
-                        <button onclick="searchAnimeOnProviders('${escapeHtml(anime.title)}')" class="btn btn-primary btn-sm">
-                            <i class="fa-solid fa-download"></i> Télécharger
+                        <button onclick="searchAnimeOnProviders('${escapeHtml(anime.title)}')" class="btn btn-success btn-sm">
+                            <i class="fa-solid fa-arrow-down"></i> Télécharger
                         </button>
                     </div>
                 </div>
@@ -397,7 +397,7 @@ function renderStreamingResult(result, query) {
     return `
         <div class="card bg-base-200 border border-base-300 shadow-sm">
             <div class="card-body p-4">
-                <div class="flex items-center justify-between mb-2">
+                <div class="flex items-center justify-between mb-3">
                     <div class="flex items-center gap-2">
                         <span class="text-lg">${icon}</span>
                         <span class="font-semibold text-sm">${escapeHtml(name)}</span>
@@ -414,9 +414,16 @@ function renderStreamingResult(result, query) {
                         ${episodes.length > 20 ? `<option disabled>... et ${episodes.length - 20} autres</option>` : ''}
                     </select>
 
-                    <button class="btn btn-primary btn-sm w-full streaming-download-btn" onclick="downloadSelectedEpisode(this)">
-                        <i class="fa-solid fa-download"></i> Télécharger
-                    </button>
+                    <div class="flex gap-2">
+                        <button class="btn btn-primary btn-sm flex-1 streaming-download-btn" onclick="downloadSelectedEpisode(this)">
+                            <i class="fa-solid fa-download"></i> Télécharger
+                        </button>
+                        <button class="btn btn-success btn-sm streaming-download-all-btn"
+                                onclick="downloadAllEpisodes(this, '${escapeHtml(query)}', '${escapeHtml(provider)}')"
+                                title="Télécharger toute la saison">
+                            <i class="fas fa-layer-group"></i>
+                        </button>
+                    </div>
                 </div>
 
                 <a href="#" class="link link-hover text-xs mt-2" onclick="searchAnimeOnProviders('${escapeHtml(query)}'); return false;">
@@ -427,6 +434,45 @@ function renderStreamingResult(result, query) {
     `;
 }
 
+// Download all episodes from a streaming result card
+async function downloadAllEpisodes(button, query, provider) {
+    const card = button.closest('.card');
+    const select = card.querySelector('.streaming-episode-select');
+    const totalEps = select.options.length - 1; // exclude disabled options
+    const hasMore = select.querySelector('option[disabled]');
+
+    button.disabled = true;
+    const originalHtml = button.innerHTML;
+    button.innerHTML = '<span class="loading loading-spinner loading-xs"></span>';
+
+    let completed = 0;
+    const promises = [];
+
+    for (const option of select.options) {
+        if (!option.value || option.disabled) continue;
+        promises.push(
+            fetch(`${API_BASE}/anime/download?url=${encodeURIComponent(option.value)}`, { method: 'POST' })
+                .then(r => { completed++; return r; })
+        );
+    }
+
+    const results = await Promise.allSettled(promises);
+    const successCount = results.filter(r => r.status === 'fulfilled').length;
+
+    button.innerHTML = '<i class="fas fa-check"></i>';
+    showToast(`${successCount} épisodes mis en file de téléchargement`);
+
+    setTimeout(() => {
+        button.innerHTML = originalHtml;
+        button.disabled = false;
+    }, 4000);
+
+    // Refresh downloads list
+    if (typeof loadDownloads === 'function') {
+        loadDownloads();
+    }
+}
+
 // Download selected episode from streaming results
 async function downloadSelectedEpisode(button) {
     const select = button.parentElement.querySelector('.streaming-episode-select');
@@ -519,7 +565,7 @@ async function translateSynopsis(synopsisId, button) {
 
             synopsisElement.textContent = data.translatedText;
             synopsisElement.dataset.translated = 'true';
-            button.innerHTML = '<i class="fa-solid fa-rotate"></i> Voir l\\'original';
+            button.innerHTML = '<i class="fa-solid fa-rotate"></i> Voir l&#39;original';
         } else {
             const errorData = await response.json().catch(() => ({ detail: 'Unknown error' }));
             console.error('Translation API error:', errorData);