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/cli/sync_dashboard.py

@@ -216,16 +216,10 @@ class SyncDashboard(App):
     .sidebar {
         width: 30;
         height: 100%;
-        border: solid $primary;
+        border: round $primary;
         padding: 0;
     }
     
-    .sidebar-title {
-        text-style: bold;
-        padding: 1;
-        background: $primary-darken-2;
-    }
-    
     .countdown-container {
         height: 5;
         padding: 0 1;
@@ -269,15 +263,10 @@ class SyncDashboard(App):
     
     .log-container {
         height: 1fr;
-        border: solid $primary;
+        border: round $primary;
         padding: 0;
     }
     
-    .log-title {
-        padding: 0 1;
-        background: $primary-darken-2;
-    }
-    
     ListView {
         height: 1fr;
     }
@@ -338,8 +327,7 @@ class SyncDashboard(App):
 
         with Horizontal(classes="dashboard"):
             # Sidebar with task list
-            with Vertical(classes="sidebar"):
-                yield Static("Tasks", classes="sidebar-title")
+            with Vertical(classes="sidebar", id="tasks-sidebar"):
                 yield ListView(
                     # Stage 1: Sync local changes to server
                     TaskListItem(
@@ -416,8 +404,7 @@ class SyncDashboard(App):
                         yield Static("0%", id="progress-percent")
 
                 # Log for selected task
-                with Vertical(classes="log-container"):
-                    yield Static("Activity Log", classes="log-title")
+                with Vertical(classes="log-container", id="log-container"):
                     yield Log(id="task-log")
 
         yield Footer()
@@ -427,6 +414,13 @@ class SyncDashboard(App):
         # Set theme from shared config
         self.theme = get_theme_name()
 
+        # Set border titles
+        try:
+            self.query_one("#tasks-sidebar").border_title = "Tasks"
+            self.query_one("#log-container").border_title = "Activity Log"
+        except Exception:
+            pass
+
         # Store references to task items
         task_list = self.query_one("#task-list", ListView)
         for item in task_list.children: