Fix TUI bugs: folder selection, filter stability, UI consistency

- Mail: Fix folder/account selector not triggering reload (use direct
  fetch instead of reactive reload_needed flag)
- Tasks: Store all_projects/all_tags on mount so filters don't change
  when filtering; add OR search for multiple tags
- Sync: Use rounded borders and border_title for sidebar/activity log
- Calendar: Remove padding from mini-calendar, add rounded border and
  border_title to invites panel

src/mail/app.py

@@ -353,7 +353,9 @@ class EmailViewerApp(App):
                 self.current_message_id = 0
                 self.current_message_index = 0
                 self.selected_messages.clear()
-                self.reload_needed = True
+                self.search_query = ""  # Clear search when switching folders
+                # Directly fetch instead of relying on reload_needed watcher
+                self.fetch_envelopes()
         except Exception as e:
             logging.error(f"Error selecting folder: {e}")
 
@@ -372,9 +374,11 @@ class EmailViewerApp(App):
                 self.current_message_id = 0
                 self.current_message_index = 0
                 self.selected_messages.clear()
+                self.search_query = ""  # Clear search when switching accounts
                 # Refresh folders for new account
                 self.fetch_folders()
-                self.reload_needed = True
+                # Directly fetch instead of relying on reload_needed watcher
+                self.fetch_envelopes()
         except Exception as e:
             logging.error(f"Error selecting account: {e}")