rename admin-submit-wrap → admin-form-footer across all templates and CSS

- Updated 6 admin templates: add.php, edit.php, login.php, account.php,
  import.php, pages-edit.php — replaced <div class="admin-submit-wrap">
  with <div class="admin-form-footer">
- Updated 8 CSS selectors in admin.css:
  - .admin-form-footer { margin-top/padding-top } (was .admin-submit-wrap)
  - .admin-form > div:not(.admin-form-footer) grid exclusion guard (×3)
  - .admin-login-box .admin-form > div:not(.admin-form-footer) overrides (×2)
  - .admin-login-box .admin-form-footer compact spacing override
- No visual change; purely a semantic rename to a descriptive class name
- Also marked status-badge.php partial and WCAG 1.3.1 badge tasks as
  already-done in todo/02-php-components.md and todo/04-accessibility.md
  (partial + CSS were fully implemented but todo had not been updated)

TODO.md

@@ -26,3 +26,6 @@ Pending tasks have been split into topic files under [`todo/`](todo/README.md):
 - [x] `add.php` / `edit.php` — `autocomplete="name"` on author field, `autocomplete="email"` on contact field
 - [x] `tags.php` — all inline `style=` attributes removed; sizing/spacing moved to CSS (`.admin-input--inline`, `.admin-select--inline`, `.admin-inline-form + .admin-inline-form`, `.admin-tags-count`)
 - [x] Marked already-done items in todo files: stats `<dl>`, `thanks.php` `<section>`, `scope="col"` on both tables, `tfe.php` inline styles, `role="alert"` on flash messages
+
+- [x] `admin-submit-wrap` → `admin-form-footer` rename: updated all 6 admin templates (`add.php`, `edit.php`, `login.php`, `account.php`, `import.php`, `pages-edit.php`) and all 8 CSS selectors in `admin.css` (`.admin-form > div:not(…)` exclusion guards, `.admin-login-box` overrides). Closes `todo/01-css-semantic-refactor.md` submit-wrap task.
+- [x] Marked `status-badge.php` partial and WCAG 1.3.1 status-badge items as already-done in `todo/02-php-components.md` and `todo/04-accessibility.md` (partial + CSS were fully implemented; TODO had not been updated)