Fix note-field space bar hijacking video, rework Outline topics as documents

- Lesson page's global keyboard shortcuts (space/arrows for play-pause/
  seek/volume) fired regardless of focus, so typing a space in the notes
  textarea toggled the video instead of typing. Now skipped entirely
  whenever a text field/select has focus.
- Outline topics no longer spawn their own top-level collection each time.
  A topic is now a document inside one fixed, user-configured collection
  (Settings -> Outline Integration -> Default collection), and a lesson's
  note becomes a child document nested under its topic - matching how
  notes actually get organized in a real Outline instance instead of
  cluttering the collections list with one per topic.

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

templates/lesson_view.html

@@ -606,11 +606,11 @@
             const topicStatus = document.getElementById('outline-topic-status');
 
             if (topicSelect) {
-                fetch('/api/outline/collections')
+                fetch('/api/outline/topics')
                     .then(r => r.json())
                     .then(data => {
                         const newOption = topicSelect.querySelector('option[value="__new__"]');
-                        (data.collections || []).forEach(function(c) {
+                        (data.topics || []).forEach(function(c) {
                             const opt = document.createElement('option');
                             opt.value = c.id;
                             opt.textContent = c.name;
@@ -624,7 +624,7 @@
                             newTopicInput.value = INITIAL_TOPIC_NAME;
                         }
                         if (data.error && topicStatus) {
-                            topicStatus.textContent = 'Outline not reachable - topic list may be incomplete';
+                            topicStatus.textContent = data.error;
                         }
                     })
                     .catch(() => {});
@@ -805,8 +805,17 @@
                 }, 3000);
             }
 
-            // Keyboard shortcuts
+            // Keyboard shortcuts - skip while typing in the note (or any
+            // other text field), so space/arrow keys type normally instead
+            // of hijacking video playback.
+            function isTypingTarget(el) {
+                if (!el) return false;
+                const tag = el.tagName;
+                return tag === 'TEXTAREA' || tag === 'INPUT' || tag === 'SELECT' || el.isContentEditable;
+            }
+
             document.addEventListener('keydown', function(e) {
+                if (isTypingTarget(e.target)) return;
                 if (activeMedia && !e.ctrlKey && !e.altKey && !e.metaKey) {
                     switch(e.key) {
                         case ' ':