fix(FN-2714): restore task timer chip to footer metadata row

- Move TaskCard time indicator rendering from the header back into the footer metadata row
- Render timer and files-changed metadata together in the shared footer row layout
- Update timer chip CSS to stay right-aligned with margin-left:auto and prevent shrinking
- Update TaskCard and mobile board tests to assert footer placement and alignment behavior

packages/dashboard/app/components/TaskCard.css

@@ -482,6 +482,8 @@
   display: inline-flex;
   align-items: center;
   gap: var(--space-xs);
+  margin-left: auto;
+  flex-shrink: 0;
   padding: var(--space-xs) var(--space-sm);
   border: 1px solid color-mix(in srgb, var(--text-muted) 30%, transparent);
   border-radius: var(--radius-pill);