fix(editor): polish project picker and scene description UX

Validate unique campaign names, add search, flip menus at scroll end, drop TipTap links, and scroll long description previews.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/renderer/editor/EditorApp.module.css

@@ -259,6 +259,17 @@
   font: inherit;
 }
 
+.fileMenuItemDanger {
+  text-align: left;
+  padding: 10px;
+  border-radius: var(--radius-sm);
+  border: none;
+  background: transparent;
+  color: var(--color-danger);
+  cursor: pointer;
+  font: inherit;
+}
+
 .fileMenuSubHost {
   position: relative;
 }
@@ -688,7 +699,8 @@
 
 .descriptionPreview {
   max-height: 4.6em;
-  overflow: hidden;
+  overflow-x: hidden;
+  overflow-y: auto;
   padding: 8px 10px;
   border-radius: var(--radius-md);
   border: 1px solid var(--stroke);
@@ -697,7 +709,6 @@
   font-size: var(--text-xs);
   line-height: 1.45;
   word-break: break-word;
-  pointer-events: none;
 }
 
 .descriptionPreview :global(p),