feat(desktop): theme polish, prose chat typography, composer chrome

- DS tokens/midground, Backdrop, scoped scrollbars, typography plugin + prose
- Composer liquid/radius utilities, thread font parity, tool/thinking cues
- File tree label scale, preview flex, thread retry loading + streaming tests

apps/desktop/package.json

@@ -47,17 +47,21 @@
     "@chenglou/pretext": "^0.0.6",
     "@hermes/shared": "file:../shared",
     "@nanostores/react": "^1.1.0",
+    "@nous-research/ui": "^0.12.0",
     "@radix-ui/react-slot": "^1.2.4",
     "@streamdown/code": "^1.1.1",
     "@tabler/icons-react": "^3.41.1",
+    "@tailwindcss/typography": "^0.5.19",
     "@tailwindcss/vite": "^4.2.4",
     "@tanstack/react-query": "^5.100.6",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
     "cmdk": "^1.1.1",
     "ignore": "^7.0.5",
+    "leva": "^0.10.1",
     "liquid-glass-react": "^1.1.1",
     "lucide-react": "^0.577.0",
+    "motion": "^12.38.0",
     "nanostores": "^1.3.0",
     "radix-ui": "^1.4.3",
     "react": "^19.2.5",