Add publish-to-pages agent skill

Agent skill that publishes presentations and web content to GitHub Pages.
Works with any AI coding agent (Copilot CLI, Claude Code, Gemini CLI, etc.)

Features:
- Converts PPTX with full formatting preservation
- Creates repo, enables Pages, returns live URL
- Zero config — just needs gh CLI

Repo: https://github.com/AndreaGriffiths11/publish-to-pages
Landing page: https://andreagriffiths11.github.io/publish-to-pages-site/

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: AndreaGriffiths11

plugins/external.json

@@ -16,5 +16,22 @@
       "repo": "microsoft/azure-skills",
       "path": ".github/plugins/azure-skills"
     }
+  },
+  {
+    "name": "publish-to-pages",
+    "description": "Agent skill that publishes presentations and web content to GitHub Pages. Give it a file (HTML, PPTX, PDF, or Google Slides URL) — get a live URL. Works with any AI coding agent. Converts PPTX with full formatting preservation. Creates repo, enables Pages, returns live URL. Zero config — just needs gh CLI.",
+    "version": "1.0.0",
+    "author": {
+      "name": "Andrea Griffiths",
+      "url": "https://github.com/AndreaGriffiths11"
+    },
+    "homepage": "https://andreagriffiths11.github.io/publish-to-pages-site/",
+    "keywords": ["github-pages", "publishing", "presentations", "pptx", "pdf", "html", "agent-skill"],
+    "license": "MIT",
+    "repository": "https://github.com/AndreaGriffiths11/publish-to-pages",
+    "source": {
+      "source": "github",
+      "repo": "AndreaGriffiths11/publish-to-pages"
+    }
   }
 ]

skills/publish-to-pages/SKILL.md

@@ -0,0 +1,89 @@
+---
+name: publish-to-pages
+description: 'Publish presentations and web content to GitHub Pages. Converts PPTX, PDF, HTML, or Google Slides to a live GitHub Pages URL. Handles repo creation, file conversion, Pages enablement, and returns the live URL. Use when the user wants to publish, deploy, or share a presentation or HTML file via GitHub Pages.'
+---
+
+# publish-to-pages
+
+Publish any presentation or web content to GitHub Pages in one shot.
+
+## 1. Prerequisites Check
+
+Run these silently. Only surface errors:
+
+```bash
+command -v gh >/dev/null || echo "MISSING: gh CLI — install from https://cli.github.com"
+gh auth status &>/dev/null || echo "MISSING: gh not authenticated — run 'gh auth login'"
+command -v python3 >/dev/null || echo "MISSING: python3 (needed for PPTX conversion)"
+```
+
+`pandoc` is optional (PDF conversion). Don't block on it.
+
+## 2. Input Detection
+
+Determine input type from what the user provides:
+
+| Input | Detection |
+|-------|-----------|
+| HTML file | Extension `.html` or `.htm` |
+| PPTX file | Extension `.pptx` |
+| PDF file | Extension `.pdf` |
+| Google Slides URL | URL contains `docs.google.com/presentation` |
+
+Ask the user for a **repo name** if not provided. Default: filename without extension.
+
+## 3. Conversion
+
+### HTML
+No conversion needed. Use the file directly as `index.html`.
+
+### PPTX
+Run the conversion script:
+```bash
+python3 SKILL_DIR/scripts/convert-pptx.py INPUT_FILE /tmp/output.html
+```
+If `python-pptx` is missing, tell the user: `pip install python-pptx`
+
+### PDF
+Convert with pandoc:
+```bash
+pandoc INPUT_FILE -o /tmp/output.html --self-contained
+```
+If pandoc is missing, tell the user to install it or provide HTML instead.
+
+### Google Slides
+1. Extract the presentation ID from the URL (the long string between `/d/` and `/`)
+2. Download as PPTX:
+```bash
+curl -L "https://docs.google.com/presentation/d/PRESENTATION_ID/export/pptx" -o /tmp/slides.pptx
+```
+3. Then convert the PPTX using the convert script above.
+
+## 4. Publishing
+
+### Visibility
+Repos are created **public** by default. If the user specifies `private` (or wants a private repo), use `--private` — but note that GitHub Pages on private repos requires a Pro, Team, or Enterprise plan.
+
+### Publish
+```bash
+bash SKILL_DIR/scripts/publish.sh /path/to/index.html REPO_NAME public "Description"
+```
+
+Pass `private` instead of `public` if the user requests it.
+
+The script creates the repo, pushes `index.html`, and enables GitHub Pages.
+
+## 5. Output
+
+Tell the user:
+- **Repository:** `https://github.com/USERNAME/REPO_NAME`
+- **Live URL:** `https://USERNAME.github.io/REPO_NAME/`
+- **Note:** Pages takes 1-2 minutes to go live.
+
+## Error Handling
+
+- **Repo already exists:** Suggest appending a number (`my-slides-2`) or a date (`my-slides-2026`).
+- **Pages enablement fails:** Still return the repo URL. User can enable Pages manually in repo Settings.
+- **PPTX conversion fails:** Tell user to run `pip install python-pptx`.
+- **PDF conversion fails:** Suggest installing pandoc or converting to HTML manually.
+- **Google Slides download fails:** The presentation may not be publicly accessible. Ask user to make it viewable or download the PPTX manually.