Stop resetting lesson progress on view, and add Notes Hub search

view_lesson() called update_lesson_progress() with no arguments on
every page load, which defaults completed=False and progress_seconds=0
and silently overwrote whatever was already saved - just opening an
already-watched lesson reset its progress/completed state unless the
client happened to report real values within the next 15 seconds.
Replaced with touch_lesson_accessed(), which only bumps last_accessed.

Also fixes the "Resume from Xs" feature this fed into: it read a value
that was never populated on this route, and even when given a real
one, checked activeMedia.duration synchronously before metadata had
loaded, so it silently never applied. Now waits for loadedmetadata (or
resolves immediately if already available) and defers to an explicit
note-timestamp jump (?t=) when both are present.

Notes Hub gets a live search box filtering by note text, lesson title,
or course name (client-side, no reload), with a "no notes match" state
- useful now that a single category folder can hold dozens of courses'
worth of timestamped notes.

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

templates/notes_hub.html

@@ -117,6 +117,17 @@
             text-align: center;
             padding: 40px 20px;
         }
+        .notes-search-input {
+            width: 100%;
+            background: var(--bg-tertiary);
+            color: var(--text-primary);
+            border: 1px solid var(--border-color);
+            border-radius: var(--radius);
+            padding: 10px 14px;
+            font-size: 0.95em;
+            font-family: var(--font-family);
+            margin-bottom: 20px;
+        }
         .note-card {
             background: var(--bg-secondary);
             border-radius: var(--radius);
@@ -213,10 +224,14 @@
 
         {% if not notes %}
         <div class="empty-hint">No notes yet - jot something down on a lesson page and it'll show up here.</div>
+        {% else %}
+        <input type="text" id="notes-search-input" class="notes-search-input"
+               placeholder="Search notes, lessons, or courses…" oninput="filterNotes(this.value)">
+        <div id="notes-no-results-hint" class="empty-hint" style="display: none;">No notes match your search.</div>
         {% endif %}
 
         {% for note in notes %}
-        <div class="note-card">
+        <div class="note-card" data-search="{{ (note.lesson_title ~ ' ' ~ note.course_name ~ ' ' ~ note.text) | lower }}">
             <div class="note-card-header">
                 <span class="note-card-icon">📝</span>
                 <div class="note-card-titles">
@@ -251,6 +266,22 @@
         </div>
     </footer>
 
+    <script>
+        function filterNotes(query) {
+            const q = query.trim().toLowerCase();
+            const cards = document.querySelectorAll('.note-card');
+            let visibleCount = 0;
+            cards.forEach(function(card) {
+                const match = !q || card.dataset.search.includes(q);
+                card.style.display = match ? '' : 'none';
+                if (match) visibleCount++;
+            });
+            const noResultsHint = document.getElementById('notes-no-results-hint');
+            if (noResultsHint) {
+                noResultsHint.style.display = (visibleCount === 0 && cards.length > 0) ? 'block' : 'none';
+            }
+        }
+    </script>
     <script src="/static/theme.js"></script>
 </body>
 </html>