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/components/a-icon-button.html

@@ -1 +1,3 @@
-<a class="{{ classes }}"{{ attrs|safe }}><div class="h-4 w-4">{{ body|safe }}</div></a>
+<a class="{{ classes }}"{{ attrs|safe }}>
+  <div class="h-4 w-4">{{ body|safe }}</div>
+</a>