feat: fix Cmd-K shortcut and add exchange full-text search to command palette

- Add missing onOpen prop to CommandPalette (fixes Ctrl+K/Cmd+K)
- Wire server-side exchange search with debounced text query
- Use design system dev snapshot from Gitea registry in CI builds

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

ui/Dockerfile

@@ -5,6 +5,7 @@ ARG REGISTRY_TOKEN
 COPY package.json package-lock.json .npmrc ./
 RUN echo "//gitea.siegeln.net/api/packages/cameleer/npm/:_authToken=${REGISTRY_TOKEN}" >> .npmrc && \
     npm ci && \
+    npm install @cameleer/design-system@dev && \
     rm -f .npmrc
 
 COPY . .