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/components/message-part.tsx

@@ -146,6 +146,7 @@ export default function MessagePart(props: MessagePartProps) {
                 sessionId={props.sessionId}
                 isDark={isDark()}
                 size={isAssistantMessage() ? "tight" : "base"}
+                escapeRawHtml={props.messageType === "user"}
                 onRendered={props.onRendered}
               />
             </Show>