feat(client): improve accessibility with ARIA labels and semantics

- Add aria-label to icon-only ActionIcon triggers across tree, comments,
  share, group, breadcrumbs, templates, AI chat, API keys, and spaces
- Give custom clickable divs/spans (color swatches, status swatches,
  load-more, PDF error, comment selection) role="button", tabIndex,
  and keyboard handlers
- Add listbox/combobox semantics (role, aria-selected, aria-activedescendant)
  to slash menu, emoji menu, mention list, and link editor results
- Add aria-haspopup/aria-expanded to bubble-menu triggers (node, text
  align, color) and status badge
- Add aria-label to Modal.Root/Dialog instances that lack a title prop
  (page history, template preview, trash preview, drawio, comment,
  find-and-replace, page verification)
- Add en-US translations for new aria-label strings

apps/client/public/locales/en-US/translation.json

@@ -880,5 +880,24 @@
   "Try a different search term.": "Try a different search term.",
   "Try again": "Try again",
   "Untitled chat": "Untitled chat",
-  "What can I help you with?": "What can I help you with?"
+  "What can I help you with?": "What can I help you with?",
+  "Page menu": "Page menu",
+  "Expand": "Expand",
+  "Collapse": "Collapse",
+  "Comment menu": "Comment menu",
+  "Group menu": "Group menu",
+  "Show hidden breadcrumbs": "Show hidden breadcrumbs",
+  "Breadcrumbs": "Breadcrumbs",
+  "Page actions": "Page actions",
+  "Pick emoji": "Pick emoji",
+  "Template menu": "Template menu",
+  "Chat menu": "Chat menu",
+  "API key menu": "API key menu",
+  "Jump to comment selection": "Jump to comment selection",
+  "Slash commands": "Slash commands",
+  "Mention suggestions": "Mention suggestions",
+  "Link suggestions": "Link suggestions",
+  "Diagram editor": "Diagram editor",
+  "Add comment": "Add comment",
+  "Find and replace": "Find and replace"
 }