feat(webmail): conversations - list, stacked reader, inline reply, settings switch

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

services/webmail/src/lib/renderMessage.ts

@@ -0,0 +1,34 @@
+import { sanitizeEmailHtml, blockRemoteImages, unblockRemoteImages } from "./sanitizer";
+import { resolveInlineImages, buildReaderDocument, type InlineImages } from "./emailBody";
+
+/** What it takes to draw a message's body. */
+export interface RenderableBody {
+  html: string;
+  inline_images?: InlineImages;
+}
+
+/**
+ * The document the reader frame renders, or null for a message with no HTML.
+ *
+ * Order matters: sanitise first so nothing downstream handles untrusted
+ * markup, then resolve the message's own inline parts, then block or restore
+ * remote sources - which is the only part the reader chooses.
+ */
+export function messageDocument(message: RenderableBody, showImages: boolean): string | null {
+  if (!message.html) return null;
+  const sanitized = sanitizeEmailHtml(message.html);
+  if (!sanitized) return null;
+  const withInline = resolveInlineImages(sanitized, message.inline_images ?? {});
+  const body = showImages ? unblockRemoteImages(withInline) : blockRemoteImages(withInline);
+  return buildReaderDocument(body);
+}
+
+/**
+ * Whether anything was actually held back, so the privacy bar is not shown over
+ * a message that has no remote content at all.
+ */
+export function hasBlockedRemoteContent(message: RenderableBody): boolean {
+  if (!message.html) return false;
+  const sanitized = resolveInlineImages(sanitizeEmailHtml(message.html), message.inline_images ?? {});
+  return blockRemoteImages(sanitized) !== sanitized;
+}