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).

public/translations/en/default.json

@@ -162,10 +162,6 @@
   "nsfw_boards_only": "NSFW Boards Only",
   "worksafe_boards_only": "Worksafe Boards Only",
   "link_type": "Link type",
-  "comment_edited_at_timestamp": "Comment edited at <1>{{timestamp}}</1>",
-  "reason_reason": "Reason: \"{{reason}}\".",
-  "click_here_to_show_original": "<1>Click here</1> to show the original.",
-  "click_here_to_hide_original": "<1>Click here</1> to hide the original.",
   "loading": "Loading",
   "posted_by": "Posted by",
   "by": "by",
@@ -412,5 +408,13 @@
   "board_address_unverified_warning": "This board address is not verified. The board owner might not own this address.",
   "post_form_rules_faq_prompt": "Please read the <rules>Rules</rules> and <faq>FAQ</faq> before posting.",
   "pending_mod_approval_reason": "AI moderation sent this post to the mod queue. Reason: \"{{reason}}\".",
-  "flag": "Flag"
+  "flag": "Flag",
+  "show_replies": "show replies",
+  "hide_replies": "hide replies",
+  "unhide": "unhide",
+  "account_data": "account data",
+  "ban_duration_days": "ban duration in days",
+  "challenge_answer": "challenge answer",
+  "ban": "ban",
+  "timestamp": "timestamp"
 }