Fix white native form fields on classic edit screens (v2.7.1)

Native form fields (title inputs, textareas, selects) on screens that
don't use the block editor — most visibly Edit Media's title field —
were showing stark white, breaking the dark theme. WP core styles some
fields via a 2-ID selector (#titlediv #title { background: #fff }),
which beats native-dark.css's existing form-field rule regardless of
class count, same specificity trap as an earlier block-editor
background bug. Added !important to the whole form-field rule block —
safe everywhere, no legitimate case for a native admin field to stay
white.

Verified this one rule fixes Edit Media, Edit Post (classic fields),
and Comment edit simultaneously; Add User was already clean. The
WYSIWYG editor body staying white is a separate, deliberate decision
(matches the block editor's own canvas) and wasn't touched.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

app/package.json

@@ -1,6 +1,6 @@
 {
   "name": "aurora-admin-app",
-  "version": "2.7.0",
+  "version": "2.7.1",
   "private": true,
   "type": "module",
   "scripts": {