CUB-45: AgentCard final integration with sub-components

- Assemble AgentCard from AgentStatusBadge, TaskProgressBar, QuickJumpButton
- All 6 inputs functional: status, task, progress, sessionKey, channel, lastActivity
- Left-border accent matches status color (Active: #38BDF8, Idle: #2DD4BF, Thinking: #A78BFA, Error: #F87171)
- Accessibility: role="article" on card, aria-labels on all sections
- Uses tactical dark mode CSS variables from CUB-47
- Added @Input() to QuickJumpButton sessionKey for parent binding
- JumpClick output forwarded from AgentCard
- Build passes, type checking passes

frontend/src/app/components/agent-status-badge/agent-status-badge.component.html

@@ -0,0 +1,12 @@
+<!-- Agent Status Badge: colored pill with pulse animation -->
+<span
+  class="status-badge"
+  [class]="statusClass"
+  [attr.aria-label]="statusLabels[status] + ' status'"
+  [attr.role]="'status'"
+>
+  <span class="status-badge__dot"></span>
+  <span *ngIf="showLabel" class="status-badge__label">
+    {{ statusLabels[status] }}
+  </span>
+</span>