style(templates): format Selmer .html templates for readability

Many templates were minified onto a single line. Reformatted every template under
resources/templates/ with djLint (django profile, 2-space indent) so the markup,
{% %} blocks, and {{ }} interpolations are human-readable, plus hand-split the two
multi-<span> option partials (invoice-option / rule-option). Pure reflow — no markup,
tag, or text content changed (the only content-adjacent delta is harmless trailing
whitespace inside single-interpolation elements). link.html / panel-empty.html stay on
one line (single element). resources/public/index.html left as-is (already readable,
non-template static).

Full e2e suite 72/72 green (no rendering regressions).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

resources/templates/transaction-edit/simple-mode.html

@@ -1,4 +1,14 @@
 {# Simple mode: a single account row (account typeahead + location select) rendered at a
    fixed index 0, plus the link to switch to the advanced grid. Selecting the account
    swaps just the location cell (#simple-account-location). #}
-<div><span>{{ row_id_hidden|safe }}<div class="flex gap-2 mt-2">{{ account_field|safe }}<div id="simple-account-location">{{ location_field|safe }}</div>{{ amount_hidden|safe }}</div></span><div class="mt-1"><a class="text-sm text-blue-600 hover:underline cursor-pointer"{{ toggle_attrs|safe }}>Switch to advanced mode</a></div></div>
+<div>
+  <span>{{ row_id_hidden|safe }}
+    <div class="flex gap-2 mt-2">
+      {{ account_field|safe }}
+      <div id="simple-account-location">{{ location_field|safe }}</div>
+      {{ amount_hidden|safe }}
+    </div>
+  </span>
+  <div class="mt-1"><a class="text-sm text-blue-600 hover:underline cursor-pointer"
+   {{ toggle_attrs|safe }}>Switch to advanced mode</a></div>
+</div>