fix(frontend): serve zone detail static export fallback

internal/router/root/frontend_static_test.go

@@ -0,0 +1,74 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package root
+
+import (
+	"testing"
+	"testing/fstest"
+)
+
+func TestResolveNextExportDynamicFallbackUsesZoneTemplate(t *testing.T) {
+	subFS := fstest.MapFS{
+		"index.html":      &fstest.MapFile{Data: []byte("dashboard")},
+		"websites/1.html": &fstest.MapFile{Data: []byte("zone detail")},
+		"websites/1.txt":  &fstest.MapFile{Data: []byte("zone flight")},
+		"websites/1/__next.!KG1haW4p.websites.$d$zoneId.__PAGE__.txt": &fstest.MapFile{Data: []byte("zone segment")},
+	}
+
+	tests := []struct {
+		name  string
+		input string
+		want  string
+	}{
+		{name: "html", input: "websites/3", want: "websites/1.html"},
+		{name: "route payload", input: "websites/3.txt", want: "websites/1.txt"},
+		{
+			name:  "segment payload",
+			input: "websites/3/__next.!KG1haW4p.websites.$d$zoneId.__PAGE__.txt",
+			want:  "websites/1/__next.!KG1haW4p.websites.$d$zoneId.__PAGE__.txt",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, ok := resolveNextExportDynamicFallback(subFS, tt.input)
+			if !ok {
+				t.Fatal("expected dynamic websites route fallback")
+			}
+			if got != tt.want {
+				t.Fatalf("expected %q fallback, got %q", tt.want, got)
+			}
+		})
+	}
+}
+
+func TestResolveNextExportDynamicFallbackRejectsNestedOrAssetPath(t *testing.T) {
+	subFS := fstest.MapFS{
+		"websites/1.html": &fstest.MapFile{Data: []byte("zone detail")},
+	}
+
+	tests := []string{
+		"websites",
+		"websites/3/settings",
+		"websites/3.js",
+		"websites/3/",
+		"websites/3/missing.txt",
+	}
+	for _, tt := range tests {
+		t.Run(tt, func(t *testing.T) {
+			if got, ok := resolveNextExportDynamicFallback(subFS, tt); ok {
+				t.Fatalf("expected no fallback, got %q", got)
+			}
+		})
+	}
+}
+
+func TestResolveNextExportDynamicFallbackRequiresGeneratedTemplate(t *testing.T) {
+	subFS := fstest.MapFS{
+		"index.html": &fstest.MapFile{Data: []byte("dashboard")},
+	}
+
+	if got, ok := resolveNextExportDynamicFallback(subFS, "websites/3"); ok {
+		t.Fatalf("expected no fallback without generated template, got %q", got)
+	}
+}