fix(ui): escape raw HTML in user prompt messages (#260)

## Summary
- escape raw HTML when rendering user message markdown so prompt input
is shown as text instead of injected HTML
- keep assistant and tool markdown behavior unchanged by scoping the
escape behavior to user messages
- update markdown cache keys so escaped and non-escaped render output do
not collide

## Verification
- `npm run typecheck --workspace @codenomad/ui` *(fails in this
workspace because frontend dependencies are not installed)*
- `npm run build --workspace @codenomad/ui` *(fails in this workspace
because `vite` is not installed)*

--
Yours,
[CodeNomadBot](https://github.com/NeuralNomadsAI/CodeNomad)

Co-authored-by: Shantur <shantur@Mac.home>

packages/ui/src/lib/markdown.ts

@@ -11,6 +11,7 @@ let highlighterPromise: Promise<Highlighter> | null = null
 let currentTheme: "light" | "dark" = "light"
 let isInitialized = false
 let highlightSuppressed = false
+let escapeRawHtmlEnabled = false
 let rendererSetup = false
 let shikiModulePromise: Promise<typeof import("shiki/bundle/full")> | null = null
 let bundledLanguagesCache: typeof import("shiki/bundle/full")["bundledLanguages"] | null = null
@@ -285,6 +286,14 @@ function setupRenderer(isDark: boolean) {
     return `<code class="inline-code">${escapeHtml(decoded)}</code>`
   }
 
+  renderer.html = (html: string) => {
+    if (!escapeRawHtmlEnabled) {
+      return html
+    }
+
+    return escapeHtml(decodeHtmlEntities(html))
+  }
+
   marked.use({ renderer })
   rendererSetup = true
 }
@@ -308,6 +317,7 @@ export async function renderMarkdown(
   content: string,
   options?: {
     suppressHighlight?: boolean
+    escapeRawHtml?: boolean
   },
 ): Promise<string> {
   if (!isInitialized) {
@@ -316,6 +326,7 @@ export async function renderMarkdown(
   }
 
   const suppressHighlight = options?.suppressHighlight ?? false
+  const escapeRawHtml = options?.escapeRawHtml ?? false
   const decoded = decodeHtmlEntities(content)
 
   if (!suppressHighlight) {
@@ -324,13 +335,16 @@ export async function renderMarkdown(
   }
 
   const previousSuppressed = highlightSuppressed
+  const previousEscapeRawHtml = escapeRawHtmlEnabled
   highlightSuppressed = suppressHighlight
+  escapeRawHtmlEnabled = escapeRawHtml
 
   try {
     // Proceed to parse immediately - highlighting will be available on next render
     return marked.parse(decoded) as Promise<string>
   } finally {
     highlightSuppressed = previousSuppressed
+    escapeRawHtmlEnabled = previousEscapeRawHtml
   }
 }