fix(ui): fix overlapping header elements on narrow screens (#31)

- Calendar toolbar now wraps view buttons to a second row on viewports
  < 580px so nav controls and label stay readable on all iOS devices
- Tasks toolbar title no longer bleeds over action buttons; uses
  min-width:min-content so flex-wrap kicks in before overflow occurs
- Shopping list-header name gets flex:1/overflow:hidden so it truncates
  cleanly instead of colliding with the clear-checked / delete buttons

public/styles/tasks.css

@@ -41,8 +41,11 @@
 .tasks-toolbar__title {
   font-size: var(--text-2xl);
   font-weight: var(--font-weight-bold);
-  flex: 1;
-  min-width: 0;
+  flex: 1 1 auto;
+  min-width: min-content;
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
 }
 
 .tasks-toolbar__actions {