fixing folders and image rendering in client

internal/webui/webmail_inline_images_test.go

@@ -0,0 +1,33 @@
+package webui
+
+import (
+	"strings"
+	"testing"
+
+	"mailgoserver/internal/mailview"
+)
+
+func TestInlineContentIDImagesReplacesWithDataURI(t *testing.T) {
+	html := `<p><img src="cid:img1@example.com"></p>`
+	attachments := []mailview.Attachment{
+		{Filename: "header.png", ContentType: "image/png", Data: []byte("fake-png-bytes"), ContentID: "img1@example.com"},
+	}
+	got := inlineContentIDImages(html, attachments)
+	if strings.Contains(got, "cid:") {
+		t.Errorf("cid: reference survived: %q", got)
+	}
+	if !strings.Contains(got, "data:image/png;base64,") {
+		t.Errorf("expected a data: URI in %q", got)
+	}
+}
+
+func TestInlineContentIDImagesLeavesUnmatchedRefsAlone(t *testing.T) {
+	html := `<p><img src="cid:unknown@example.com"></p>`
+	// No attachment carries this Content-Id — must not touch the src, since
+	// htmlBodyPolicy.Sanitize (run right after this) already strips any src it
+	// doesn't recognize, and that's the correct outcome for a genuinely missing part.
+	got := inlineContentIDImages(html, nil)
+	if got != html {
+		t.Errorf("got %q, want unchanged", got)
+	}
+}