feat: persist sidebar state

internal/middleware/sidebar.go

@@ -0,0 +1,21 @@
+package middleware
+
+import (
+	"net/http"
+
+	"git.juancwu.dev/juancwu/budgit/internal/ctxkeys"
+)
+
+// WithSidebarState reads the sidebar_state cookie and adds the collapsed
+// state to the request context so templates can render the sidebar in the
+// correct initial state.
+func WithSidebarState(next http.Handler) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		collapsed := false
+		if c, err := r.Cookie("sidebar_state"); err == nil {
+			collapsed = c.Value == "false"
+		}
+		ctx := ctxkeys.WithSidebarCollapsed(r.Context(), collapsed)
+		next.ServeHTTP(w, r.WithContext(ctx))
+	}
+}