feat: add PageInfo model for pagination

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

models/paging.go

@@ -0,0 +1,28 @@
+package models
+
+// PageInfo carries pagination state for templates.
+type PageInfo struct {
+	CurrentPage  int
+	TotalPages   int
+	PostsPerPage int
+}
+
+// HasPrevious returns true if there is a previous page.
+func (p PageInfo) HasPrevious() bool {
+	return p.CurrentPage > 1
+}
+
+// HasNext returns true if there is a next page.
+func (p PageInfo) HasNext() bool {
+	return p.CurrentPage < p.TotalPages
+}
+
+// PreviousPage returns the previous page number.
+func (p PageInfo) PreviousPage() int {
+	return p.CurrentPage - 1
+}
+
+// NextPage returns the next page number.
+func (p PageInfo) NextPage() int {
+	return p.CurrentPage + 1
+}