fix: host modal — single POST endpoint for create+edit, remove hx-put conflict

- hx-put="" (empty) was causing HTMX to send wrong requests
- Now use single hx-post="/hosts" with hidden hostId field
- Server checks hostId: empty → create, present → update
- UpdateHost reads ID from both URL param and form data

app/backend/internal/handler/dashboard.go

@@ -51,6 +51,12 @@ func parsePort(s string, def int) int {
 }
 
 func CreateHost(c *fiber.Ctx) error {
+	hostID := c.FormValue("hostId")
+
+	if hostID != "" {
+		return UpdateHost(c)
+	}
+
 	name := c.FormValue("name")
 	ip := c.FormValue("ip")
 	if name == "" || ip == "" {
@@ -77,9 +83,8 @@ func CreateHost(c *fiber.Ctx) error {
 		h.AuthType = "key"
 	}
 
-	created := hostStore.AddFull(h)
+	hostStore.AddFull(h)
 	hosts := hostStore.All()
-	_ = created
 	return c.Render("host_list", fiber.Map{
 		"Hosts":   hosts,
 		"Active":  countByStatus(hosts, "active"),
@@ -89,6 +94,9 @@ func CreateHost(c *fiber.Ctx) error {
 
 func UpdateHost(c *fiber.Ctx) error {
 	id := c.Params("id")
+	if id == "" {
+		id = c.FormValue("hostId")
+	}
 	existing, found := hostStore.Get(id)
 	if !found {
 		return c.Status(404).SendString("host not found")