Fix the claims page's mismatched control heights, and separate approve/reject

Two things, found together while looking at the row of controls under each
pending claim.

The child dropdown stood taller than the btn-sm/input-sm around it because
ClaimReviewForm.child hardcoded its own class="select select-bordered w-full"
on the widget. templatetags/field.html's select branch already builds the
full class list itself (base classes + the size modifier), so the widget's
own class rendered as a second, non-merging class="..." attribute right next
to the generated one -- select-sm was in the markup, just shadowed by a
duplicate attribute the browser never applied. No other Select field in the
app hardcodes a class this way, which is why nothing else had the problem.
Fixed by dropping it and passing size="small" through {% form_field %}
instead, the same way every other compact inline select in the app does.

Also pulled Approve and Reject apart with justify-between rather than letting
both sit in one flex-wrap run, so they stay on opposite sides of the row
(and don't end up adjacent on a wrap) rather than one stray click apart.

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

static/css/app.css

@@ -3773,6 +3773,9 @@
   .gap-x-4 {
     column-gap: calc(var(--spacing) * 4);
   }
+  .gap-x-6 {
+    column-gap: calc(var(--spacing) * 6);
+  }
   .gap-y-2 {
     row-gap: calc(var(--spacing) * 2);
   }