Add Resume button, Surprise Me random pick, and bulk select

Three quality-of-life additions to the Library browser and course
pages:

- A course page shows a "Resume: <lesson>" button when there's a
  last-visited lesson, using Course.last_accessed_path (already
  populated by apply_progress_to_tree, just not surfaced before) -
  no more scrolling the tree to find where you left off.

- "Surprise Me" picks a random not-yet-fully-watched course and loads
  it, for when there's too much library to decide what to watch.
  Reuses the already-cached get_all_course_dirs() and the same
  per-course completed/total shape _scan_library_activity() already
  computes for Stale Courses - no new scanning.

- A select-mode toggle in the Library browser adds checkboxes to every
  row/card (list and grid) with a bulk-action bar to hide or queue
  several courses/folders at once, via two new endpoints
  (/api/hidden-paths/bulk, /api/next-up/bulk) that reuse the existing
  single-item set_path_hidden()/set_path_queued() in a loop. Selection
  is scoped to the current folder view and clears on navigation.

Also fixes runTranscriptSearch() going silently blank on zero results
instead of showing a "no matches" message, and updates the Help page
to cover all of this.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

templates/course_dashboard.html

@@ -248,6 +248,25 @@
             background: #555;
         }
 
+        .resume-btn {
+            display: block;
+            width: 100%;
+            text-align: center;
+            margin-top: 12px;
+            font-size: 1.05em;
+            font-weight: 600;
+            box-sizing: border-box;
+        }
+
+        .surprise-me-btn {
+            display: block;
+            width: 100%;
+            text-align: center;
+            font-size: 1.05em;
+            font-weight: 600;
+            box-sizing: border-box;
+        }
+
         .progress-bar {
             background: #444;
             border-radius: 10px;
@@ -653,6 +672,32 @@
             color: white;
             border-color: var(--accent);
         }
+        #library-select-btn {
+            border-radius: var(--radius);
+            margin-left: 4px;
+        }
+
+        .bulk-action-bar {
+            display: flex;
+            align-items: center;
+            flex-wrap: wrap;
+            gap: 8px;
+            margin-top: 10px;
+            padding: 10px;
+            background: var(--bg-tertiary);
+            border-radius: var(--radius);
+        }
+        .bulk-selected-count {
+            font-size: 0.9em;
+            color: var(--text-muted);
+            margin-right: auto;
+        }
+        .select-checkbox {
+            width: 18px;
+            height: 18px;
+            flex-shrink: 0;
+            cursor: pointer;
+        }
 
         .library-grid {
             display: grid;
@@ -881,6 +926,9 @@
         <div class="container">
             <div class="card">
                 <h2 class="course-name-heading">{{ course.name }}</h2>
+                {% if resume_lesson %}
+                <a class="btn resume-btn" href="/lesson/{{ resume_lesson.url }}">▶ Resume: {{ resume_lesson.title }}</a>
+                {% endif %}
                 <div style="display: flex; justify-content: space-between; align-items: center; margin-top: 15px; flex-wrap: wrap; gap: 10px;">
                     <div>
                         <strong>{{ stats.completed_lessons }}/{{ stats.total_lessons }}</strong> lessons completed
@@ -1028,6 +1076,10 @@
         {% endmacro %}
 
         {% if library_stats and library_stats.total_courses %}
+        <div class="container">
+            <a class="btn surprise-me-btn" href="/random-pick">🎲 Surprise Me</a>
+        </div>
+
         <div class="container">
             <div class="card">
                 <h2 class="collapsible-header" data-card-id="library-stats">📊 Library Stats</h2>
@@ -1160,11 +1212,19 @@
                         <button type="button" class="view-toggle-btn" id="library-view-grid-btn"
                                 onclick="setLibraryViewMode('grid')" title="Grid view">▦</button>
                     </div>
+                    <button type="button" class="view-toggle-btn" id="library-select-btn"
+                            onclick="toggleSelectionMode()" title="Select multiple">☑</button>
                 </div>
                 <label class="transcript-search-toggle">
                     <input type="checkbox" id="search-transcripts-toggle" onchange="handleLibrarySearchInput(document.getElementById('library-search-input').value)">
                     Also search transcripts
                 </label>
+                <div id="bulk-action-bar" class="bulk-action-bar" style="display: none;">
+                    <span id="bulk-selected-count" class="bulk-selected-count"></span>
+                    <button type="button" class="btn btn-secondary btn-sm" onclick="bulkHideSelected()">🚫 Hide Selected</button>
+                    <button type="button" class="btn btn-secondary btn-sm" onclick="bulkQueueSelected()">📌 Add to Next Up</button>
+                    <button type="button" class="btn btn-secondary btn-sm" onclick="toggleSelectionMode()">Cancel</button>
+                </div>
                 <p id="library-path-bar" class="library-breadcrumb"></p>
                 <div id="library-groups" style="margin-top: 15px;"></div>
                 <div id="transcript-results"></div>
@@ -1268,6 +1328,7 @@
 
         function fetchLibraryLevel(path) {
             searchActive = false;
+            clearSelection(); // selection is scoped to the current folder view
             const searchInput = document.getElementById('library-search-input');
             if (searchInput) searchInput.value = '';
             const transcriptResults = document.getElementById('transcript-results');
@@ -1379,13 +1440,92 @@
             if (lastLibraryItems) renderItemRows(sortLibraryItems(lastLibraryItems));
         }
 
+        // ---- Bulk select (hide / queue several courses or folders at once) ----
+        let selectionMode = false;
+        let selectedPaths = new Set();
+
+        function selectableAttrs(item) {
+            if (!selectionMode) return '';
+            const safePath = item.path.replace(/'/g, "\\'");
+            const checked = selectedPaths.has(item.path) ? 'checked' : '';
+            return `<input type="checkbox" class="select-checkbox" onclick="event.stopPropagation(); toggleSelection('${safePath}')" ${checked}>`;
+        }
+
+        function toggleSelectionMode() {
+            selectionMode = !selectionMode;
+            if (!selectionMode) selectedPaths.clear();
+            const btn = document.getElementById('library-select-btn');
+            if (btn) btn.classList.toggle('active', selectionMode);
+            updateBulkActionBar();
+            if (lastLibraryItems) renderItemRows(sortLibraryItems(lastLibraryItems));
+        }
+
+        function toggleSelection(path) {
+            if (selectedPaths.has(path)) selectedPaths.delete(path);
+            else selectedPaths.add(path);
+            updateBulkActionBar();
+            if (lastLibraryItems) renderItemRows(sortLibraryItems(lastLibraryItems));
+        }
+
+        function clearSelection() {
+            selectionMode = false;
+            selectedPaths.clear();
+            const btn = document.getElementById('library-select-btn');
+            if (btn) btn.classList.remove('active');
+            updateBulkActionBar();
+        }
+
+        function updateBulkActionBar() {
+            const bar = document.getElementById('bulk-action-bar');
+            const count = document.getElementById('bulk-selected-count');
+            if (!bar) return;
+            bar.style.display = selectedPaths.size > 0 ? 'flex' : 'none';
+            if (count) count.textContent = `${selectedPaths.size} selected`;
+        }
+
+        function bulkHideSelected() {
+            const paths = Array.from(selectedPaths);
+            fetch('/api/hidden-paths/bulk', {
+                method: 'POST',
+                headers: { 'Content-Type': 'application/json' },
+                body: JSON.stringify({ paths: paths, hidden: true })
+            })
+            .then(r => r.json())
+            .then(() => {
+                clearSelection();
+                fetchLibraryLevel(libraryTrail.length ? libraryTrail[libraryTrail.length - 1].path : null);
+            })
+            .catch(() => {});
+        }
+
+        function bulkQueueSelected() {
+            const coursePaths = Array.from(selectedPaths).filter(p => {
+                const item = (lastLibraryItems || []).find(i => i.path === p);
+                return item && item.type === 'course';
+            });
+            if (!coursePaths.length) {
+                alert('Select at least one course (not a folder) to add to Next Up.');
+                return;
+            }
+            fetch('/api/next-up/bulk', {
+                method: 'POST',
+                headers: { 'Content-Type': 'application/json' },
+                body: JSON.stringify({ paths: coursePaths })
+            })
+            .then(r => r.json())
+            .then(() => clearSelection())
+            .catch(() => {});
+        }
+
         function courseCardHtml(item) {
             const safePath = item.path.replace(/'/g, "\\'");
             const iconHtml = item.has_thumbnail
                 ? `<img class="grid-card-thumb" src="/library/thumbnail?path=${encodeURIComponent(item.path)}" alt="" onerror="this.replaceWith(gridFallbackIcon('🎓'))">`
                 : `<span>🎓</span>`;
+            const clickHandler = selectionMode ? `toggleSelection('${safePath}')` : `loadCoursePath('${safePath}')`;
             return `
-                <div class="library-grid-card" onclick="loadCoursePath('${safePath}')">
+                <div class="library-grid-card" onclick="${clickHandler}">
+                    ${selectableAttrs(item)}
                     <div class="grid-card-thumb-wrap">${iconHtml}</div>
                     <div class="grid-card-name">${item.name}</div>
                     <div class="grid-card-meta">${item.media_files} media file${item.media_files === 1 ? '' : 's'}</div>
@@ -1396,8 +1536,10 @@
         function directoryCardHtml(item) {
             const safePath = item.path.replace(/'/g, "\\'");
             const safeName = item.name.replace(/'/g, "\\'");
+            const clickHandler = selectionMode ? `toggleSelection('${safePath}')` : `enterLibraryDir('${safePath}', '${safeName}')`;
             return `
-                <div class="library-grid-card" onclick="enterLibraryDir('${safePath}', '${safeName}')">
+                <div class="library-grid-card" onclick="${clickHandler}">
+                    ${selectableAttrs(item)}
                     <div class="grid-card-thumb-wrap">📁</div>
                     <div class="grid-card-name">${item.name}</div>
                 </div>
@@ -1409,9 +1551,11 @@
             const iconHtml = item.has_thumbnail
                 ? `<img class="lesson-thumb" src="/library/thumbnail?path=${encodeURIComponent(item.path)}" alt="" onerror="this.replaceWith(courseFallbackIcon('🎓'))">`
                 : `<span class="lesson-icon">🎓</span>`;
+            const clickHandler = selectionMode ? `toggleSelection('${safePath}')` : `loadCoursePath('${safePath}')`;
             return `
-                <div class="lesson-item" onclick="loadCoursePath('${safePath}')">
+                <div class="lesson-item" onclick="${clickHandler}">
                     <div class="lesson-title">
+                        ${selectableAttrs(item)}
                         ${iconHtml}
                         <span class="lesson-name">${item.name}</span>
                     </div>
@@ -1426,9 +1570,11 @@
         function directoryRowHtml(item) {
             const safePath = item.path.replace(/'/g, "\\'");
             const safeName = item.name.replace(/'/g, "\\'");
+            const clickHandler = selectionMode ? `toggleSelection('${safePath}')` : `enterLibraryDir('${safePath}', '${safeName}')`;
             return `
-                <div class="tree-header directory" onclick="enterLibraryDir('${safePath}', '${safeName}')">
+                <div class="tree-header directory" onclick="${clickHandler}">
                     <div class="tree-title">
+                        ${selectableAttrs(item)}
                         <span class="tree-icon">📁</span>
                         <span class="tree-name">${item.name}</span>
                     </div>
@@ -1472,6 +1618,7 @@
 
         function runLibrarySearch(query) {
             searchActive = true;
+            clearSelection(); // selection is scoped to the current folder view
             const container = document.getElementById('library-groups');
             const transcriptContainer = document.getElementById('transcript-results');
             container.innerHTML = skeletonRowsHtml(2);
@@ -1508,7 +1655,7 @@
                 .then(data => {
                     const results = data.results || [];
                     if (!results.length) {
-                        transcriptContainer.innerHTML = '';
+                        transcriptContainer.innerHTML = '<p style="color:var(--text-muted); padding: 6px 0;">No matching transcripts.</p>';
                         return;
                     }
                     transcriptContainer.innerHTML = `<div style="font-weight:600; margin: 10px 0 8px; font-size: 0.9em; color: var(--text-muted);">In transcripts</div>` +
@@ -1521,7 +1668,7 @@
                         `).join('');
                 })
                 .catch(() => {
-                    transcriptContainer.innerHTML = '';
+                    transcriptContainer.innerHTML = '<p style="color:var(--error);">Transcript search failed.</p>';
                 });
         }