major architecture refactor

internal/ui/messages/messages.go

@@ -0,0 +1,20 @@
+package messages
+
+import "git.juancwu.dev/juancwu/porkbacon/internal/porkbun"
+
+type Page int
+
+const (
+	PageLogin Page = iota
+	PageMenu
+)
+
+type SwitchPageMsg struct {
+	Page Page
+}
+
+type SessionReadyMsg struct {
+	Client *porkbun.Client
+}
+
+type ErrorMsg error