v1: Add production deploy workflow (#340)

## Summary

Adds a GitHub Actions workflow to deploy to the new
`calact-network-analysis-tool-prod` Cloudflare Pages project when a
GitHub release is published. The existing Cloudflare GitHub App
continues to handle staging deploys (push to `main`) and PR preview
deployments.

### Setup required before first deploy
- Create `calact-network-analysis-tool-prod` Pages project in Cloudflare
dashboard (Direct Upload, no Git connection)
- Add GitHub Actions repo secrets: `CLOUDFLARE_API_TOKEN`,
`CLOUDFLARE_ACCOUNT_ID`, `NUXT_PUBLIC_TLV2_PROTOMAPS_APIKEY`
- Add runtime env vars in the Cloudflare Pages project settings:
`NUXT_AUTH0_DOMAIN`, `NUXT_AUTH0_CLIENT_ID`, `NUXT_AUTH0_CLIENT_SECRET`,
`NUXT_AUTH0_SESSION_SECRET`, `NUXT_AUTH0_APP_BASE_URL`,
`NUXT_AUTH0_AUDIENCE`, `NUXT_TLV2_PROXY_BASE_DEFAULT`,
`NUXT_TLV2_GRAPHQL_APIKEY`
- Add production CNAME pointing at
`calact-network-analysis-tool-prod.pages.dev`

## Test plan
- Merge and cut a test release to verify the workflow triggers and
deploys successfully
- Confirm the deployed site loads and authenticates correctly at the
production URL

closes
https://github.com/interline-io/calact-network-analysis-tool/issues/332

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