Add logbook entries, data export page, and JSON import

templates/device_detail.html

@@ -221,6 +221,37 @@ function addInstallRow() {
   {% endif %}
 </div>
 
+<div class="card">
+  <h2>Logbook</h2>
+  {% if logbook_entries %}
+    <div style="display:flex;flex-direction:column;gap:0.6rem;margin-bottom:1rem;">
+      {% for entry in logbook_entries %}
+      <div style="border-left:3px solid var(--border);padding:0.35rem 0.75rem;
+                  display:flex;justify-content:space-between;align-items:flex-start;gap:0.5rem;">
+        <div>
+          <div class="text-muted" style="font-size:0.78rem;margin-bottom:0.15rem;">{{ entry.recorded_at }}</div>
+          <div style="white-space:pre-wrap;">{{ entry.body }}</div>
+        </div>
+        <form method="post"
+              action="{{ url_for('device_logbook_delete', device_id=device.id, entry_id=entry.id) }}"
+              data-confirm="Delete this logbook entry?" data-confirm-ok="Delete">
+          <button class="btn btn-sm btn-danger" type="submit">Delete</button>
+        </form>
+      </div>
+      {% endfor %}
+    </div>
+  {% else %}
+    <p class="text-muted" style="margin-bottom:0.75rem;">No logbook entries yet.</p>
+  {% endif %}
+  <h3 style="font-size:1rem;margin:0.75rem 0 0.5rem;color:var(--text-h2);">Add Entry</h3>
+  <form method="post" action="{{ url_for('device_logbook_add', device_id=device.id) }}">
+    <div class="form-group" style="margin-bottom:0.5rem;">
+      <textarea name="body" placeholder="Write a note…" rows="2" required style="min-height:60px;"></textarea>
+    </div>
+    <button class="btn btn-primary" type="submit">Add Entry</button>
+  </form>
+</div>
+
 <div class="card">
   <h2>Edit Device</h2>
   <form method="post" action="{{ url_for('device_edit', device_id=device.id) }}">