Add Cockpit reports view

[hauptmedia]

Summary

• add a Cockpit Reports page at /reports
• wire Camunda 7 historic process duration and historic task report REST endpoints
• add filters, table rendering, CSV/JSON export buttons, navigation, translations, styles, and tests

Verification

• node -e "JSON.parse(require('fs').readFileSync('public/locales/en-US/translation.json','utf8')); JSON.parse(require('fs').readFileSync('public/locales/de-DE/translation.json','utf8')); console.log('translations ok')"
• npx eslint src/api/resources/report.js src/api/resources/report.test.js src/pages/Reports.jsx src/pages/Reports.test.jsx src/api/engine_rest.jsx src/components/GoTo.jsx src/components/GoTo.test.jsx src/components/Header.jsx src/components/Header.test.jsx src/index.jsx src/state.js src/state.test.js
• npx vitest run src/api/resources/report.test.js src/pages/Reports.test.jsx src/state.test.js src/components/GoTo.test.jsx src/components/Header.test.jsx
• npx vitest run
• npm run build
• Browser smoke: /reports reaches the login boundary without console errors; authenticated reports require a running backend accepting the dev login

[sonarqubecloud]

Quality Gate failed

Failed conditions
4.4% Duplication on New Code (required ≤ 3%)

See analysis details on SonarQube Cloud