Redeploy to pick up shared UI bundle polish

Since the phoenix-book's last deploy the wincon-antora-ui
bundle gained several code-block improvements: file-tab
titles attach flush to the code pane, the copy button moved
inside the code area (GitHub-style), and bash / iex blocks
render with a macOS-style terminal title bar (three
traffic-light dots, subtle depth, minimal in-title-bar copy
button). An empty commit is enough — Antora's deploy fetches
the fresh bundle and restamps every page with the new CSS
hash. No source changes.

Author: wintermeyer