docs: add new slide deck

[mnkiefer]

• Updates the documentation site to improve how presentation slides are handled and displayed.
• Supports multiple PDF slide decks and providing a more visual, user-friendly way to preview available slide decks.

[Copilot]

Pull request overview

Updates the docs “Presentation Slides” page to surface multiple slide decks (dated PDF exports + interactive HTML) and adjusts the docs build to publish all slide PDFs.

Changes:

• Replace the single “Open Slides / Download PDF” buttons with a thumbnail gallery linking to multiple decks.
• Update build:slides to copy all PDFs from docs/slides/ into the published public/slides/ directory.
• Add/update the slide source deck file (.pptx).

Show a summary per file

File	Description
docs/src/content/docs/introduction/slides.mdx	Switches to a gallery layout with links to multiple slide decks and adds inline CSS for the gallery.
docs/package.json	Expands the slides build step to publish all PDFs (wildcard copy).
docs/slides/github-agentic-workflows.pptx	Adds/updates the PowerPoint source for the slides deck.

Copilot's findings

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Comments suppressed due to low confidence (2)

docs/src/content/docs/introduction/slides.mdx:26

• slides/20260224-thumb.png is referenced as the preview image, but no such file exists in the repository. Add/copy the thumbnail into public/slides/ (or adjust the UI to avoid thumbnails) so the gallery doesn’t show a broken image.

    <a href={`${import.meta.env.BASE_URL}slides/20260224%20-%20GitHub%20Agentic%20Workflows.pdf`} aria-label="Open the February 24, 2026 PDF deck in the browser">
      <img
        src={`${import.meta.env.BASE_URL}slides/20260224-thumb.png`}
        alt="First slide preview for the February 24, 2026 PDF deck"
        class="slides-gallery-image"
      />

docs/src/content/docs/introduction/slides.mdx:35

• slides/index-thumb.png is referenced for the interactive deck preview, but the image file isn’t present anywhere in the repo. Please add this asset (and copy it into public/slides/ during build:slides) or remove the thumbnail reference.

    <a href={`${import.meta.env.BASE_URL}slides/`} aria-label="Open the interactive HTML deck in the browser">
      <img
        src={`${import.meta.env.BASE_URL}slides/index-thumb.png`}
        alt="First slide preview for the interactive HTML deck"
        class="slides-gallery-image"
      />

• Files reviewed: 2/5 changed files
• Comments generated: 2

[Copilot]

slides/20260407-thumb.png is referenced as the preview image, but there is no such file in the repo (not under docs/public/ or docs/slides/). This will render as a broken image; either commit the thumbnail (and ensure it’s copied into public/slides/ at build time) or change the page to not depend on a missing asset.

This issue also appears in the following locations of the same file:

• line 21
• line 30

[Copilot]

The slides page now expects thumbnail images under /slides/*-thumb.png, but build:slides only copies PDFs into public/slides/. Unless thumbnails are added/handled elsewhere, the new gallery images will 404 in production; update the build to also copy/generate the thumbnail assets (or adjust the page to not require them).

Suggested change

	"build:slides": "mkdir -p public/js && cp node_modules/mermaid/dist/mermaid.min.js public/js/ && npx @marp-team/marp-cli slides/index.md --html --allow-local-files --theme slides/gh-aw-theme.css -o public/slides/index.html && mkdir -p public/slides && cp slides/*.pdf public/slides/",
	"build:slides": "mkdir -p public/js && cp node_modules/mermaid/dist/mermaid.min.js public/js/ && npx @marp-team/marp-cli slides/index.md --html --allow-local-files --theme slides/gh-aw-theme.css -o public/slides/index.html && mkdir -p public/slides && sh -c 'for file in slides/*.pdf slides/*-thumb.png; do [ -e \"$file\" ] && cp \"$file\" public/slides/; done'",