feat: add templates for transactional emails (#103)

* add template migration & router

* template CRUD

* templated transactional emails API

* zod schema fix & rearranging template columns

apps/web/src/app/(dashboard)/dasboard-layout.tsx

@@ -11,6 +11,7 @@ import {
   Globe,
   Home,
   LayoutDashboard,
+  LayoutTemplate,
   LineChart,
   Mail,
   Menu,
@@ -67,6 +68,11 @@ export function DashboardLayout({ children }: { children: React.ReactNode }) {
                   Contacts
                 </NavButton>
 
+                <NavButton href="/templates">
+                  <LayoutTemplate className="h-4 w-4" />
+                  Templates
+                </NavButton>
+
                 <NavButton href="/campaigns">
                   <Volume2 className="h-4 w-4" />
                   Campaigns