fix(dashboard): flatten header; replace greeting with date+time; split overdue/soon chips

Header shows current date and time instead of user name + separate date line.
urgentCount replaced by overdueCount (overdue tasks) and dueSoonCount (due today/soon),
each with a distinct chip color. formatDueDate updated to accept due_time and return
accurate overdue/soon states against the current moment.
dashboard grid expands to 4 columns at 1280px instead of 1440px.

public/styles/dashboard.css

@@ -69,7 +69,7 @@
   }
 }
 
-@media (min-width: 1440px) {
+@media (min-width: 1280px) {
   .dashboard__grid {
     grid-template-columns: repeat(4, 1fr);
   }
@@ -107,10 +107,8 @@
 
 .widget-greeting__content {
   display: flex;
-  flex-direction: column;
-  gap: var(--space-0h);
-  flex: 1;
-  min-width: 0;
+  gap: var(--space-3);
+  align-items: center;
 }
 
 .widget-greeting__title {
@@ -120,7 +118,10 @@
 
 @media (min-width: 1024px) {
   .widget-greeting__title {
-    font-size: var(--text-2xl);
+    font-size: 1.4rem;
+    opacity: 0.85;
+    white-space: nowrap;
+    padding-top: 4px;
   }
 }
 
@@ -132,8 +133,9 @@
 .widget-greeting__chips {
   display: flex;
   flex-wrap: wrap;
-  gap: var(--space-2);
-  margin-top: var(--space-2);
+  margin-top: 4px;
+  align-items: center;
+  gap: var(--space-2, 8px);
 }
 
 .greeting-chip {
@@ -152,6 +154,10 @@
   background: var(--color-danger-translucent);
 }
 
+.greeting-chip--due {
+  background: rgba(245, 158, 11, 0.28);
+}
+
 /* --------------------------------------------------------
  * Basis-Widget (Card)
  *
@@ -330,6 +336,16 @@
   font-weight: var(--font-weight-medium);
 }
 
+.task-item__meta--soon {
+  color: var(--color-soon);
+  font-weight: var(--font-weight-medium);
+}
+
+.task-item__meta--overdue {
+  color: var(--color-danger);
+  font-weight: var(--font-weight-medium);
+}
+
 .task-item__avatar {
   width: var(--space-5);
   height: var(--space-5);