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/internal/handler/terminal.go

@@ -28,12 +28,14 @@ func Terminal(c *fiber.Ctx) error {
 		}
 	}
 	hostsJSON, _ := json.Marshal(available)
+	selectedHost := c.Query("host", "")
 	data := fiber.Map{
-		"View":      "terminal",
-		"Title":     "Terminal",
-		"NavItems":  navItems,
-		"Hosts":     available,
-		"HostsJSON": string(hostsJSON),
+		"View":         "terminal",
+		"Title":        "Terminal",
+		"NavItems":     navItems,
+		"Hosts":        available,
+		"HostsJSON":    string(hostsJSON),
+		"SelectedHost": selectedHost,
 	}
 	if c.Get("HX-Request") != "" {
 		return c.Render("terminal_content", data)