feat: add Pi agent blog post, AI tooling, and SVG support

Add new blog post documenting a week using the Pi CLI agent for 100% agentic development. Include AI agent configuration with custom prompts and skills to streamline content creation workflow.

- Publish "Week with my-pi-agent" article with Pi logo and screenshot assets
- Add .pi/ configuration with new-blog-post prompt and review-article skill
- Create AGENTS.md with comprehensive project documentation for AI assistants
- Fix SVG rendering to skip unsupported dimension extraction in markdown filter
- Update picture generator to handle SVG files with simple img tag
- Update syntect dependency to 5.3.0 with default-fancy features
- Swap featured segment from older post to new Pi agent article

.pi/prompts/new-blog-post.md

@@ -0,0 +1,59 @@
+---
+description: Create a new blog post with today's date and proper front matter. Takes a title/topic as argument.
+---
+Create a new blog post file for this project.
+
+**Input:** $@ - The title/topic for the blog post
+
+---
+
+## Instructions
+
+1. Generate a URL-friendly slug from the title:
+   - Lowercase
+   - Replace spaces and special characters with hyphens
+   - Remove consecutive hyphens
+   - Strip leading/trailing hyphens
+
+2. Create the file at `_posts/blog/YYYY-MM-DD-{slug}.md` where YYYY-MM-DD is today's date
+
+3. Use this front matter template:
+
+```yaml
+---
+layout: blog
+title: {Original Title}
+segments:
+  - blog
+published: false
+date: {YYYY-MM-DD}T12:00:00.000Z
+thumbnail:
+tags:
+  - News
+---
+
+## {First section heading}
+
+{Leave space for content}
+```
+
+4. **Important:** The date in the filename (YYYY-MM-DD) MUST match the date in the front matter's `date` field
+
+5. Confirm the file was created with the full path
+
+## Available Segments
+- `blog` (default)
+- `featured`
+- `broadcasts`
+- `cookbook`
+
+## Common Tags
+- News
+- Development
+- Programming
+- Rust
+- JavaScript
+- TypeScript
+- Keyboards
+- Tutorial
+- Personal