fix(client): declare browser-only externals as devDependencies

react, react-dom, shiki, katex, clsx, the micromark and mdast families and nine
more reach only browser artifacts, which resolve nothing on a user's machine.
Moving 79 declarations out of dependencies and non-optional peerDependencies
drops 103 tarballs and 6.05 MB from an install of the published CLI.

apps/web/package.json

@@ -26,9 +26,7 @@
   },
   "license": "MIT",
   "dependencies": {
-    "@deepseek-ai/dsh-client-web": "workspace:^",
-    "react": "^18.2.0",
-    "react-dom": "^18.2.0"
+    "@deepseek-ai/dsh-client-web": "workspace:^"
   },
   "devDependencies": {
     "@deepseek-ai/cordis-plugin-group": "workspace:^",
@@ -46,6 +44,8 @@
     "typescript": "^6.0.3",
     "vite": "^6.0.0",
     "vitest": "^4.1.8",
-    "fflate": "^0.8.2"
+    "fflate": "^0.8.2",
+    "react": "^18.2.0",
+    "react-dom": "^18.2.0"
   }
 }