demo: java-hotpatch polish, Slidev deck, Pages deploy workflow

- **java-hotpatch/record.sh** + asciinema cast + skills lockfile: iterative
  polish on the existing demo (continues 135e733 / a5ef031 / 1509d82) for
  reproducibility. `PricingController.java` is intentionally left with the
  VAT-on-discount bug — that's what the demo teaches.

- **Slidev deck** (`demo/slides/`) used at the Dev With AI meetup. Media
  committed except `demo-java.mp4` (32 MB), which is uploaded to the
  [demo-assets-v1](https://github.com/theodo-group/debug-that/releases/tag/demo-assets-v1)
  release and referenced by URL from `slides.md`.

- **GitHub Pages site deploy** (`.github/workflows/deploy-site.yml`):
  assembles a single artifact combining the existing landing page in
  `docs/` with the Slidev build under `/slides/`. Triggered by push to
  `main` under `docs/**` or `demo/slides/**`, plus manual dispatch.

  Landing page preserved — the existing Pages deploy at
  https://theodo-group.github.io/debug-that/ keeps working, just gets a
  new nav link to https://theodo-group.github.io/debug-that/slides/.

  **One-time repo setting change required**: switch Pages source from
  "Branch: main / /docs" to "GitHub Actions" (Settings → Pages → Source:
  GitHub Actions). After that, this workflow owns every deploy.

- `docs/index.html`: added "Slides" link to the top nav and footer.

.gitignore additions:
- `demo/**/target/`, `demo/**/.agents/`, `demo/**/.claude/` (build output
  + local tooling)
- `demo/slides/public/demo-java.mp4` (hosted on GH Releases)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: waltoss

.github/workflows/deploy-site.yml

@@ -0,0 +1,71 @@
+name: Deploy site to GitHub Pages
+
+# Assembles a single GitHub Pages site combining:
+#   - the static landing page in `docs/` (existing dbg homepage)
+#   - the Slidev deck in `demo/slides/`, built into `<site>/slides/`
+#
+# Both served from https://theodo-group.github.io/debug-that/ — landing at
+# `/`, slides at `/slides/`. Requires Pages source = "GitHub Actions" in
+# repo settings (Settings → Pages → Source: GitHub Actions). The previous
+# legacy setup (Source: Branch `main` / `/docs`) must be switched over once;
+# after that, this workflow owns every deploy.
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - "docs/**"
+      - "demo/slides/**"
+      - ".github/workflows/deploy-site.yml"
+  # Manual trigger — useful for the first deploy after flipping the Pages source.
+  workflow_dispatch:
+
+# One deploy at a time; latest push wins.
+concurrency:
+  group: pages
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: latest
+
+      - name: Install slides dependencies
+        working-directory: demo/slides
+        run: bun install --frozen-lockfile
+
+      - name: Assemble site (docs landing + slides)
+        run: |
+          mkdir -p _site
+          # Copy existing static landing page as-is.
+          cp -R docs/. _site/
+          # Build Slidev into _site/slides. The --base path matches where
+          # it'll be served (Pages serves this repo's site under /debug-that/).
+          cd demo/slides
+          bunx slidev build --base /debug-that/slides/ --out "$GITHUB_WORKSPACE/_site/slides"
+
+      - uses: actions/configure-pages@v5
+
+      - uses: actions/upload-pages-artifact@v3
+        with:
+          path: _site
+
+  deploy:
+    needs: build
+    runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deploy.outputs.page_url }}
+    steps:
+      - id: deploy
+        uses: actions/deploy-pages@v4

.gitignore

@@ -49,3 +49,11 @@ src/dap/adapters/java/adapter-sources.tar.gz
 demo/**/recording.cast
 demo/**/__hotpatch_tmp/
 docs/java-hotpatch.gif
+
+# Demo build output / local tooling
+demo/**/target/
+demo/**/.agents/
+demo/**/.claude/
+
+# Large demo video — hosted on GitHub Releases (demo-assets-v1) instead
+demo/slides/public/demo-java.mp4