css: replace admin-form-row/admin-label/admin-input/select/textarea classes with semantic selectors

Remove five presentational classes from admin forms and replace with
structural CSS selectors scoped to .admin-form:

- .admin-form-row  → .admin-form > div:not(.admin-submit-wrap)
  Grid layout (260px label col + 1fr input col) applied directly to div
  children of the form; submit-wrap div excluded via :not().

- .admin-label     → .admin-form > div:not(.admin-submit-wrap) > label
  Scoped to the direct label child of each form row div; does not bleed
  into nested checkbox labels inside .admin-checkbox-list.

- .admin-input / .admin-select / .admin-textarea
  → .admin-form input:not([type=checkbox|radio|file|hidden|submit])
  → .admin-form select
  → .admin-form textarea
  Also extended to .admin-inline-form input/select (tags page) so the
  tags table inputs retain identical base styling and focus colour.

Templates updated: add.php, edit.php, login.php, account.php,
pages-edit.php, import.php, tags.php,
templates/partials/form/jury-fieldset.php — all class= attributes for
the five removed classes stripped.

import.php: added 'admin-form' class alongside 'admin-import-area' so
its single file-input row gets the grid row treatment; submit div was
already using admin-submit-wrap so it is correctly excluded.

No visual change — selectors target the same elements as before.

public/assets/css/admin.css

@@ -110,7 +110,7 @@
   gap: 0;
 }
 
-.admin-form-row {
+.admin-form > div:not(.admin-submit-wrap) {
   display: grid;
   grid-template-columns: 260px 1fr;
   align-items: start;
@@ -119,20 +119,23 @@
   gap: 1rem;
 }
 
-.admin-form-row:last-of-type {
+.admin-form > div:not(.admin-submit-wrap):last-of-type {
   border-bottom: 1px solid var(--admin-border);
 }
 
-.admin-label {
+.admin-form > div:not(.admin-submit-wrap) > label {
   font-size: 0.92rem;
   color: var(--admin-text);
   padding-top: 0.5rem;
   font-weight: 400;
 }
 
-.admin-input,
-.admin-select,
-.admin-textarea {
+.admin-form input:not([type="checkbox"]):not([type="radio"]):not([type="file"]):not([type="hidden"]):not([type="submit"]),
+.admin-form select,
+.admin-form textarea,
+.admin-inline-form input[type="text"],
+.admin-inline-form input[type="number"],
+.admin-inline-form select {
   width: 100%;
   background: var(--admin-input-bg);
   border: none;
@@ -147,26 +150,29 @@
   appearance: none;
 }
 
-.admin-input:focus,
-.admin-select:focus,
-.admin-textarea:focus {
+.admin-form input:not([type="checkbox"]):not([type="radio"]):not([type="file"]):not([type="hidden"]):not([type="submit"]):focus,
+.admin-form select:focus,
+.admin-form textarea:focus,
+.admin-inline-form input:focus,
+.admin-inline-form select:focus {
   border-bottom-color: var(--admin-purple);
 }
 
-.admin-input::placeholder,
-.admin-textarea::placeholder {
+.admin-form input::placeholder,
+.admin-form textarea::placeholder {
   color: var(--admin-text-muted);
   font-size: 0.88rem;
 }
 
-.admin-textarea {
+.admin-form textarea {
   resize: vertical;
   min-height: 100px;
   line-height: 1.5;
 }
 
 /* Select custom arrow */
-.admin-select {
+.admin-form select,
+.admin-inline-form select {
   cursor: pointer;
   background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%23888' stroke-width='1.5' fill='none' stroke-linecap='round'/%3E%3C/svg%3E");
   background-repeat: no-repeat;
@@ -174,7 +180,8 @@
   padding-right: 1.2rem;
 }
 
-.admin-select option {
+.admin-form select option,
+.admin-inline-form select option {
   background: var(--admin-bg);
   color: var(--admin-text);
 }
@@ -598,13 +605,13 @@
   text-align: center;
 }
 
-.admin-login-box .admin-form-row {
+.admin-login-box .admin-form > div:not(.admin-submit-wrap) {
   grid-template-columns: 1fr;
   border: none;
   padding: 0.4rem 0;
 }
 
-.admin-login-box .admin-label {
+.admin-login-box .admin-form > div:not(.admin-submit-wrap) > label {
   font-size: 0.82rem;
   color: var(--admin-text-muted);
   padding: 0;
@@ -692,12 +699,14 @@
   flex-wrap: wrap;
 }
 
-.admin-input--inline {
+.admin-input--inline,
+.admin-inline-form input[type="text"] {
   padding: 0.28rem 0.5rem;
   font-size: 0.82rem;
 }
 
-.admin-select--inline {
+.admin-select--inline,
+.admin-inline-form select {
   padding: 0.28rem 0.5rem;
   font-size: 0.82rem;
 }