fix: update DS to v0.1.31, simplify env selector styles

DS v0.1.31 changes .env wrapper to neutral button style matching
other TopBar controls. Simplified selector CSS to inherit all
font/color properties from the wrapper.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/package-lock.json

@@ -8,7 +8,7 @@
       "name": "ui",
       "version": "0.0.0",
       "dependencies": {
-        "@cameleer/design-system": "^0.1.30",
+        "@cameleer/design-system": "^0.1.31",
         "@tanstack/react-query": "^5.90.21",
         "lucide-react": "^1.7.0",
         "openapi-fetch": "^0.17.0",
@@ -278,9 +278,9 @@
       }
     },
     "node_modules/@cameleer/design-system": {
-      "version": "0.1.30",
-      "resolved": "https://gitea.siegeln.net/api/packages/cameleer/npm/%40cameleer%2Fdesign-system/-/0.1.30/design-system-0.1.30.tgz",
-      "integrity": "sha512-HK8bQlp7NU1GIZAT17gjyeN/NQVDdpQiUmphFJ/f+y4nS+FsbCcI+Qtq67S9+DZeu33+7L/NFUDRVYBTjuX20w==",
+      "version": "0.1.31",
+      "resolved": "https://gitea.siegeln.net/api/packages/cameleer/npm/%40cameleer%2Fdesign-system/-/0.1.31/design-system-0.1.31.tgz",
+      "integrity": "sha512-yfuMQdLB3RS6loT31YozKCyBUnctxlLPZjpzPzD7UQZhCFU4+ScibMzbPeLFE/MyMkfrpk/j9v8pJCHW7l64TQ==",
       "dependencies": {
         "lucide-react": "^1.7.0",
         "react": "^19.0.0",