fix(react): address Doctor findings (#1143)

Accessibility/semantics pass aligned with React Doctor: role-based spans/divs become real buttons, role=status becomes <output>, modals use native <dialog>, author/peer flags render as <img>, and embed/challenge iframes are sandboxed. Includes review follow-ups: correct button chrome/centering/themed dialog colors and focus rings, the missing aria-label i18n keys (all languages), the Yandex image-search URL, clearer .bso setup steps, a keyboard-accessible image-search dropdown, and removal of the post-edit ('comment edited') display (mod edits unchanged).

src/components/board-pagination/__tests__/board-pagination.test.tsx

@@ -90,7 +90,7 @@ describe('BoardPagination', () => {
     expect(container.textContent).toContain('catalog');
     expect(container.textContent).toContain('archive');
 
-    const allLink = Array.from(container.querySelectorAll<HTMLElement>('[role="button"]')).find((element) => element.textContent === 'all');
+    const allLink = Array.from(container.querySelectorAll<HTMLButtonElement>('button')).find((element) => element.textContent === 'all');
     expect(allLink).toBeTruthy();
 
     await act(async () => {

src/components/board-pagination/board-pagination.tsx

@@ -45,9 +45,9 @@ const BoardPagination = ({ basePath, currentPage, search = '', totalPages, foote
             {currentPage === 1 && (
               <span className={styles.footerPageItem}>
                 <span className={styles.footerPageBracket}>[</span>
-                <span
+                <button
+                  type='button'
                   className={styles.footerPageLink}
-                  role='button'
                   tabIndex={0}
                   onClick={() => setEnableInfiniteScroll(true)}
                   onKeyDown={(e) => {
@@ -58,7 +58,7 @@ const BoardPagination = ({ basePath, currentPage, search = '', totalPages, foote
                   }}
                 >
                   {t('all')}
-                </span>
+                </button>
                 <span className={styles.footerPageBracket}>]</span>
               </span>
             )}