Ship containers/quantecon-preview: slim TeX-free preview image with pinned deploy CLI

[mmcky]

#92 Phase 2: ship containers/quantecon-preview — a slim preview image (~1.7 GB zstd vs 2,741 MB for quantecon-build, 1,233 MB of which is TeXLive that an HTML-only preview never uses).

• Drop the TeX layer; drop the jupyter metapackage (it transitively reinstalls jupyterlab); keep MKL/ipykernel for execution parity
• Bake the pinned preview-deploy CLI — per the QuantEcon/infrastructure#4 migration this is now wrangler (≥ 4.21.0, see Add Workers static assets support to the Cloudflare preview action #145), not netlify-cli
• Switch lecture-dp ci/cache/publish to it (consumer half)
• Add a stack-pins-match assertion to test-container.yml so the preview image cannot drift from the build image — :latest reaches consumers ungated by any release

Not started — no containers/quantecon-preview exists.