feat: responsive compact mail view + folder unread badges

- CompactMailDelegate: card-based view for narrow panels (<420px)
  * Avatar with hash-based color, sender + date (relative format)
  * Subject line with attachment icon
  * Action buttons: flag, delete, category, more (context menu)
  * Unread highlight with light blue background + bold sender
- MailListView: automatic switch between tree/table (wide) and list/cards (narrow)
  * QStackedWidget with QTreeView + QListView sharing same proxy model
  * resizeEvent threshold at 420px
  * Signals forwarded to MainMainWindow for actions
- FolderTreeDelegate: custom paint for folder tree
  * Unread count badge (blue pill) right-aligned on folder nodes
  * Account nodes bold, folder nodes normal weight
  * Proper indentation per depth level
- MailItemDao::countUnreadByFolderId() for real-time unread counts
- MainMainWindow handlers for compact actions (flag, delete, category, more menu)

build/CMakeFiles/InstallScripts.json

@@ -1,7 +1,7 @@
 {
 	"InstallScripts" : 
 	[
-		"/mnt/c/Users/javie/wino-mail-dtkqt/build/cmake_install.cmake"
+		"/mnt/c/Users/javie/Documents/Codex/2026-08-11/revisar-2/wino-mail-dtkqt/build/cmake_install.cmake"
 	],
 	"Parallel" : false
 }