feat: Host CRUD complete — edit, full form fields, connect, toast

- Add UpdateHost handler + PUT /hosts/:id route
- CreateHost now accepts all fields (port, username, auth, notes)
- host_modal.html: full form with port, username, auth type toggle, edit mode
- host_list.html: edit button dispatches edit-host event with host data
- Connect button links to /terminal?host={id} for pre-selection
- Terminal page reads selected host from query param
- Toast notification system via Alpine.js events
- Add default template function for fallback values

app/backend/static/js/terminal.js

@@ -1,6 +1,8 @@
 document.addEventListener('alpine:init', () => {
   const el = document.getElementById('hosts-data');
   const hostOptions = el ? JSON.parse(el.textContent) : [];
+  const selEl = document.getElementById('selected-host');
+  const selectedHostId = selEl ? JSON.parse(selEl.textContent) : '';
 
   function processCommand(cmd, tabName) {
     const lines = [];
@@ -86,9 +88,15 @@ document.addEventListener('alpine:init', () => {
     },
 
     addTab() {
-      const host = hostOptions.length > 0
-        ? hostOptions[Math.floor(Math.random() * hostOptions.length)]
-        : { id: 'h1', name: 'localhost', ip: '127.0.0.1' };
+      let host;
+      if (selectedHostId) {
+        host = hostOptions.find(h => h.id === selectedHostId) || hostOptions[0];
+      }
+      if (!host) {
+        host = hostOptions.length > 0
+          ? hostOptions[Math.floor(Math.random() * hostOptions.length)]
+          : { id: 'h1', name: 'localhost', ip: '127.0.0.1' };
+      }
       const id = 'tab-' + Date.now() + '-' + Math.random().toString(36).slice(2, 6);
       this.tabs.push({ id, name: host.name, host: host.ip, connected: true });
       this.activeTab = this.tabs.length - 1;