Extract dashboard row and sync-all form into reusable partials

These render the initial dashboard page today and will also be
rendered standalone by the sync routes in the next commits, so the
same markup drives both the full page and the post-sync response.

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

app/web/templates/fragments/toast.html

@@ -0,0 +1,3 @@
+<div id="toast-container" hx-swap-oob="true">
+    <div class="toast toast-{{ level }}">{{ message }}</div>
+</div>