feat(terminal): add Terminal panel to Node Details with WebSocket

- Add 'Terminal' button to drawer header

- Implement TerminalPanel (bottom-up fade-in, ~1/3 viewport, left of drawer)

- Connect to ws(s)://{nodeIp}/ws; display incoming messages; input sends raw

- Wire Drawer to pass node IP and close terminal on drawer close

- Add styles/z-index and include script in index.html

public/index.html

@@ -177,6 +177,7 @@
     <script src="./scripts/view-models.js"></script>
     <!-- Base/leaf components first -->
     <script src="./scripts/components/DrawerComponent.js"></script>
+    <script src="./scripts/components/TerminalPanelComponent.js"></script>
     <script src="./scripts/components/PrimaryNodeComponent.js"></script>
     <script src="./scripts/components/NodeDetailsComponent.js"></script>
     <script src="./scripts/components/ClusterMembersComponent.js"></script>