feat: enhance daemon dispatching, device readiness fallback, and live streaming UI

- Admin Console & Task Queue: add cancellation, session startup progress endpoints, and support ingress metadata
- Diagnostics & Runtime: enhance ADB probe to prefer unlocked devices and synchronize with readiness engine
- MCP Server: dispatch tasks through Artemis Daemon scheduler with fallback to standalone runner, improve action overlays
- Showcase UI: improve session auto-selection with pinning support, render startup progress, and refine stream styling
- CLI & Makefile: expose server lifecycle commands (restart, stop, status)
- Configuration: ignore runtime server state file in .gitignore

apps/showcase_ui/src/app/components/chat-interface/chat-interface.component.scss

@@ -297,11 +297,14 @@ $text-muted: #a1a1aa;
 
         .task-card-header .task-card-header-actions {
           &:has(.btn-delete-card) .task-time,
-          &:has(.btn-delete-card) .task-time-divider {
+          &:has(.btn-delete-card) .task-time-divider,
+          &:has(.btn-stop-card) .task-time,
+          &:has(.btn-stop-card) .task-time-divider {
             opacity: 0;
           }
 
-          .btn-delete-card {
+          .btn-delete-card,
+          .btn-stop-card {
             opacity: 1;
             pointer-events: auto;
           }
@@ -508,6 +511,43 @@ $text-muted: #a1a1aa;
               cursor: not-allowed;
             }
           }
+
+          .btn-stop-card {
+            position: absolute;
+            right: 0;
+            top: 50%;
+            transform: translateY(-50%);
+            width: 20px;
+            height: 20px;
+            padding: 0;
+            border: none;
+            background: transparent;
+            border-radius: 4px;
+            color: #ef4444;
+            cursor: pointer;
+            display: inline-flex;
+            align-items: center;
+            justify-content: center;
+            opacity: 0;
+            pointer-events: none;
+            transition: all 0.15s ease;
+
+            .material-symbols-outlined {
+              font-size: 15px;
+              line-height: 1;
+            }
+
+            &:hover:not(:disabled) {
+              color: #dc2626;
+              background: #fee2e2;
+              transform: translateY(-50%) scale(1.1);
+            }
+
+            &:disabled {
+              opacity: 0.3;
+              cursor: not-allowed;
+            }
+          }
         }
       }