Remove unused components and assets from the project

Deleted unused components (Attachments, CustomMarkdownRenderer, EnableSearchButton, FlyoutSubMenu) and associated styles (katex.css) to streamline the codebase. This cleanup helps reduce technical debt and improve project maintainability.

package.json

@@ -61,7 +61,6 @@
     "js-cookie": "^3.0.5",
     "katex": "^0.16.20",
     "lucide-react": "^0.436.0",
-    "manifold-workflow-engine": "^2.0.2",
     "marked": "^15.0.4",
     "marked-extended-latex": "^1.1.0",
     "marked-footnote": "^1.2.4",
@@ -75,15 +74,8 @@
     "react": "^18.3.1",
     "react-dom": "^18.3.1",
     "react-icons": "^5.4.0",
-    "react-markdown": "^9.0.1",
     "react-streaming": "^0.3.44",
     "react-textarea-autosize": "^8.5.5",
-    "rehype-katex": "^7.0.1",
-    "rehype-react": "^8.0.0",
-    "remark-gfm": "^4.0.0",
-    "remark-math": "^6.0.0",
-    "remark-parse": "^11.0.0",
-    "remark-rehype": "^11.1.1",
     "shiki": "^1.24.0",
     "terser": "^5.39.0",
     "typescript": "^5.7.2",