docs: move the agent guide to AGENTS.md and bring it up to date

.github/copilot-instructions.md

@@ -1,195 +1,5 @@
-# QuantEcon Website
+# Copilot instructions
 
-The QuantEcon website is a Jekyll-based static site that serves as the main portal for QuantEcon, a nonprofit organization providing open source computational tools for economics, econometrics, and decision making.
+The guide for AI agents and contributors to this repository is [AGENTS.md](../AGENTS.md), at the repository root. Read it before you change anything: it covers the project, the repository layout, the commands, the CI checks and how to run them, where each kind of content goes, the gotchas, and the pull request and commit conventions.
 
-**Always reference these instructions first and fallback to search or bash commands only when you encounter unexpected information that does not match the info here.**
-
-## Working Effectively
-
-### Bootstrap and Build the Repository
-
-Install bundler and set up the development environment:
-- `gem install bundler --user-install` - Install bundler locally (required for Jekyll)
-- `export PATH="$HOME/.local/share/gem/ruby/3.4.0/bin:$PATH"` - Add bundler to PATH
-- `bundle config set --local path 'vendor/bundle'` - Configure local gem installation path
-- `bundle install` - Install Jekyll dependencies (takes ~30 seconds)
-
-Build the static site:
-- `bundle exec jekyll build` - Build the site (takes ~1-2 seconds). **NEVER CANCEL**: Fast build, 5 second timeout is sufficient.
-- Output goes to `_site/` directory
-
-### Development Server
-
-Run the Jekyll development server:
-- `bundle exec jekyll serve --host 0.0.0.0 --port 4000` - Start development server (takes ~2 seconds to start)
-- Access the site at `http://localhost:4000`
-- **NEVER CANCEL**: Server startup is fast, but may run indefinitely for development
-- Use `Ctrl+C` to stop the server when done
-
-### Repository Structure
-
-Key directories and files:
-- `_config.yml` - Jekyll configuration file
-- `Gemfile` - Ruby dependencies specification
-- `_layouts/` - Jekyll layout templates (home.html, default.html, post.html, etc.)
-- `_includes/` - Jekyll include templates (quantecon-menubar.html)
-- `_posts/` - News posts, written by people (sorted chronologically)
-- `_data/activity/` - Activity feed data (library releases, lecture updates), written by the reporter bot — see "News and Activity" in README.md
-- `_plugins/` - Jekyll plugins, which every build runs: `activity_generator.rb` and `activity/rows.rb` compute the Activity rows as `site.data.activity_view` — see "Activity rows" in README.md
-- `_lectures/` - Collection of lecture series pages
-- `_projects/` - Collection of project pages  
-- `_team-members/` - Collection of team member profiles
-- `pages/` - Static pages (about.md, lectures.md, workshops.md, etc.)
-- `assets/` - Static assets (images, CSS, JavaScript)
-  - `assets/js/main.js` - Main JavaScript file
-  - `assets/sass/` - SCSS stylesheets
-  - `assets/img/` - Images and graphics
-- `_site/` - Generated static site (excluded from git)
-- `vendor/` - Bundler gems (excluded from git)
-
-### Common Operations
-
-**Adding new content:**
-- News posts: Add markdown files to `_posts/` with format `YYYY-MM-DD-title.md` — only for announcements (new projects, grants, people, workshops); releases and lecture updates belong in Activity (see "News and Activity" in README.md)
-- Team members: Add markdown files to `_team-members/` — `role` picks the section on the team page and `tag` the badge; the Translators section instead lists anyone with a `translator` field (e.g. `translator: "Chinese Editor"`), so a member can appear there as well as in their own section
-- Lectures: Add markdown files to `_lectures/`
-- Workshops: Add to `pages/workshops.md` **and** update the hardcoded "Recent Workshops" list in `_layouts/home.html` (see #197 for planned automation)
-- Static pages: Add markdown files to `pages/`
-
-**Editing existing content:**
-- All content uses markdown with Jekyll front matter
-- Edit the appropriate markdown file in the relevant directory
-- Run `bundle exec jekyll build` to regenerate the site
-- Test changes with `bundle exec jekyll serve`
-
-## Validation
-
-**Always validate changes by testing complete user scenarios:**
-1. Build the site: `bundle exec jekyll build`
-2. Start the development server: `bundle exec jekyll serve --host 0.0.0.0 --port 4000`
-3. Open browser to `http://localhost:4000`
-4. Navigate through the main sections:
-   - Home page - verify layout and content load
-   - Lectures page - verify lecture series are listed
-   - News page - verify news posts display
-   - Activity page - verify entries from `_data/activity/` display, grouped by month
-   - About page - verify team information
-   - Navigation menu - verify all links work
-5. Test responsive design by resizing browser window
-6. Verify images and styling load correctly
-
-**Automated checks** - CI's `build` job runs these checks before it builds the site. Run them locally the same way, with plain `ruby` (minitest isn't in the Gemfile, so not with `bundle exec`):
-- `ruby .github/scripts/check-activity-data.rb` - checks the Activity data files in `_data/activity/` against the schema in README.md
-- `ruby .github/scripts/test-activity.rb` - tests the Activity rows plugin (`_plugins/activity/`) with minitest, against a frozen copy of the data in `.github/scripts/fixtures/activity/` and against the live data
-
-Everything else is validated through manual browser testing.
-
-**No linting or formatting commands** - the repository has minimal tooling beyond Jekyll itself.
-
-## Dependencies and Requirements
-
-**Ruby Environment:**
-- Ruby 3.4+
-- Bundler gem manager
-- Jekyll 4.4 (specified in Gemfile)
-
-**Key Jekyll plugins used:**
-- jekyll-feed - RSS feed generation
-- jekyll-redirect-from - URL redirects
-- minima - Base theme
-- webrick - Development server
-- `_plugins/activity_generator.rb` - this repository's own generator, which every build runs: it computes `site.data.activity_view` from `_data/activity/` (see "Activity rows" in README.md)
-
-**No Node.js, npm, or JavaScript build tools required** - this is a pure Jekyll/Ruby environment.
-
-## Troubleshooting
-
-**Permission errors during bundle install:**
-- Use `bundle config set --local path 'vendor/bundle'` to install gems locally
-- Never use `sudo` with gem commands
-
-**Build failures:**
-- Check that Ruby 3.4+ is installed
-- Verify all dependencies installed with `bundle install`
-- Clear cache with `bundle exec jekyll clean` before rebuilding
-- `Activity data: <file>, entry <n> (<project>): …` means the Activity rows plugin can't use that entry, for example because its `type` is unknown: fix the file and entry it names, then run `ruby .github/scripts/check-activity-data.rb` to check every Activity file against the schema
-
-**Server access issues:**
-- Ensure server is bound to `0.0.0.0` not just `127.0.0.1`
-- Check port 4000 is not in use by another process
-- Access via `http://localhost:4000` not `0.0.0.0`
-
-## Important Information
-
-**Build times:**
-- Bundle install: ~30 seconds
-- Jekyll build: 1-2 seconds (very fast)
-- Server startup: ~2 seconds
-
-**Git workflow:**
-- `vendor/` and `.bundle/` directories are gitignored (contain local gems)
-- `_site/` directory is gitignored (contains generated output)
-- Only source files should be committed
-
-**External dependencies:**
-- Site loads external JavaScript libraries from CDNs (Bootstrap, AOS, Swiper, etc.)
-- Some JavaScript errors may appear in browser console due to blocked CDN requests in development environments
-- These errors don't affect core site functionality
-
-## Common Tasks Reference
-
-### Frequently used commands
-```bash
-# Setup (run once after clone)
-gem install bundler --user-install
-export PATH="$HOME/.local/share/gem/ruby/3.4.0/bin:$PATH"
-bundle config set --local path 'vendor/bundle'
-bundle install
-
-# Development workflow
-bundle exec jekyll build
-bundle exec jekyll serve --host 0.0.0.0 --port 4000
-
-# Clean build (if needed)
-bundle exec jekyll clean
-bundle exec jekyll build
-```
-
-### Repository root listing
-```
-├── .gitignore
-├── .prettierignore  
-├── CNAME
-├── Gemfile
-├── README.md
-├── _config.yml
-├── _data/activity/
-├── _includes/
-├── _layouts/
-├── _lectures/
-├── _plugins/
-├── _posts/ 
-├── _projects/
-├── _team-members/
-├── archive/
-├── assets/
-├── feed.xml
-├── index.md
-├── pages/
-└── sitemap.xml
-```
-
-### Key files content
-
-**Gemfile dependencies:**
-- jekyll ~> 4.4
-- minima ~> 2.5
-- jekyll-feed ~> 0.17
-- jekyll-redirect-from
-- webrick ~> 1.8
-
-**_config.yml key settings:**
-- Site title: QuantEcon
-- Timezone: Australia/Sydney
-- Collections: news, lectures, projects, team-members
-- Plugins: jekyll-redirect-from
+Copilot code review on GitHub.com, the Copilot cloud agent, Copilot CLI and Copilot Chat in VS Code read AGENTS.md directly. This file is for the Copilot features that read only this path, such as Copilot Chat on GitHub.com and code review in an IDE, so keep it to this pointer and make changes in AGENTS.md.