fix(editor): improve mention card sizing and vertical alignment

- Restore card to readable size (py-0.5, px-2, text-xs, rounded-md)
- Add max-w-72 and truncate on title for long issue names
- Move vertical-align: middle to [data-node-view-wrapper] (outermost
  inline element) instead of inner <a> — fixes centering within line
- Always render card style even when issue not in store (fallback shows
  identifier only)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/web/features/editor/content-editor.css

@@ -301,7 +301,6 @@
 .rich-text-editor a.issue-mention {
   color: inherit;
   text-decoration: none;
-  vertical-align: middle;
 }
 
 .rich-text-editor a.issue-mention:hover {
@@ -339,6 +338,7 @@
 /* Mention NodeView inline layout fix */
 .rich-text-editor [data-node-view-wrapper] {
   display: inline;
+  vertical-align: middle;
 }
 
 /* Images — shared styling for both editing and readonly */