Better parsing of pasted html as markdown so agents understand (#9190)

Signed-off-by: Douwe Osinga <douwe@squareup.com>
Co-authored-by: Douwe Osinga <douwe@squareup.com>

ui/desktop/package.json

@@ -96,6 +96,7 @@
     "swr": "^2.4.0",
     "tailwind-merge": "^3.5.0",
     "tailwindcss-animate": "^1.0.7",
+    "turndown": "^7.2.4",
     "tw-animate-css": "^1.4.0",
     "unist-util-visit": "^5.1.0",
     "uuid": "^13.0.0",
@@ -132,6 +133,7 @@
     "@types/react-dom": "^19.2.3",
     "@types/react-syntax-highlighter": "^15.5.13",
     "@types/shell-quote": "^1.7.5",
+    "@types/turndown": "^5.0.6",
     "@types/yauzl": "^2.10.3",
     "@typescript-eslint/eslint-plugin": "^8.56.1",
     "@typescript-eslint/parser": "^8.56.1",