[erkamyaman]

What and why

Moves the image to slide.ng 2.0.0 and follows its command line. Merge after @slide-ng/core 2.0.0 is on npm (the default build installs it from npm; a tarball in packages/ works today).

• The Dockerfile, docker-compose.yml and .env.example install @slide-ng/core@2.0.0 by default (was 0.1.0).
• 2.0 builds and exports several decks at once (slide-ng build a.md b.md, each deck in <out>/<name>/, served under <base><name>/). build, export, export-notes, serve and watch now pass every .md file named after the mode; a flag's .md value (--output talk.md) is not taken for a deck. dev still runs one deck.
• serve.mjs serves such a build: an address gets the index.html of its deck's folder, <base>a redirects to <base>a/, and the base lists the decks.
• 2.0 moves the inline scripts of index.html into inline-<hash>.js files, so a strict Content-Security-Policy works. serve.mjs now caches them like the other hashed files.
• skills is passed to slide-ng like format.
• README: several decks, --router-mode (passed through; hash and memory builds need nothing from the server) and CSP (serve.mjs sends none; put a real web server in front, see slide.ng's HOSTING.md). CHANGELOG updated.

How I checked it

• bash tests/entrypoint.test.sh: 75 passed (new cases for several decks, the .md flag value, the deck list, the redirect, the inline-*.js caching and skills). bash tests/commit-msg.test.sh: 14 passed.
• shellcheck -x entrypoint.sh tests/*.sh .githooks/commit-msg (0.11.0) and hadolint Dockerfile (2.15.1): pass.
• docker compose config: parses.
• Built the image on Docker 29.8.2 (Linux) with SLIDE_NG_SOURCE=packages/slide-ng-core-2.0.0.tgz; slide-ng --version prints 2.0.0. The build machine reaches Debian and npm only through an HTTPS proxy, so the test copy of the Dockerfile sent apt and npm through it; nothing else differed.
• In the container: build --base /talk/, build --router-mode hash, export --format pdf (deck mounted :ro, --shm-size=1g), export a.md b.md, serve a.md b.md --base /x/ (both decks and the presenter opened in Chromium without errors), watch, dev with a password, serve with --read-only --tmpfs /tmp --cap-drop ALL, and docker compose --profile build run --rm build. All worked.
• Not run: the GitHub Actions workflow, and watch with a read-only root.

Checklist

• bash tests/entrypoint.test.sh and bash tests/commit-msg.test.sh pass.
• shellcheck -x and hadolint pass.
• I built and ran the image (with the 2.0.0 tarball; see above for the proxy note).
• I updated the README for a changed variable, port or mode.
• I kept the security defaults: non-root user, a password for dev, compose ports on 127.0.0.1.
• I agree that my contribution is under the MIT license.