Add comprehensive GitHub Copilot instructions for awesome-avalonia repository (#219)

* Initial plan

* Add comprehensive GitHub Copilot instructions for awesome-avalonia repository

Co-authored-by: OmidID <[email protected]>

---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: OmidID <[email protected]>

Author: Copilot

.github/copilot-instructions.md

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+# Awesome Avalonia Curation Repository
+
+Awesome Avalonia is a curated list of Avalonia UI libraries, tools, samples, and resources maintained in a single README.md file. This is a documentation-only repository with no build processes or code compilation.
+
+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
+
+### Repository Structure
+- `README.md` - The main awesome list containing all Avalonia resources organized by categories
+- `CONTRIBUTING.md` - Guidelines for contributors submitting new entries
+- `.github/workflows/link-check.yml` - Weekly automated link validation
+- `.gitignore` and `.gitattributes` - Standard Git configuration files
+
+### Essential Commands
+- Install the markdown link checker: `cargo install mlc`
+- Check all links: `/home/runner/.cargo/bin/mlc . --throttle 100` 
+- Check specific file: `/home/runner/.cargo/bin/mlc README.md --throttle 100`
+- View link checker help: `/home/runner/.cargo/bin/mlc --help`
+
+### Link Validation - NEVER CANCEL
+- **CRITICAL**: Link checking takes 22-25 seconds. NEVER CANCEL. Set timeout to 60+ minutes.
+- The tool checks 299+ links across the repository
+- Expect 40-50 broken links due to site changes, redirects, or temporary outages
+- Exit code 1 is NORMAL when broken links are found - this is not a failure
+- Use `--throttle 100` to avoid being rate-limited by external sites
+- Both commands (`mlc .` and `mlc README.md`) produce identical results since only README.md contains links
+
+### Timing Expectations
+- **Link checking**: 22-25 seconds for full repository check. NEVER CANCEL.
+- **Manual validation**: 2-3 minutes to verify new entries follow format guidelines
+- **Content editing**: Immediate - no build or compilation steps required
+
+## Validation
+
+### Pre-commit Validation Steps
+ALWAYS run these commands before committing changes:
+1. `cd /home/runner/work/awesome-avalonia/awesome-avalonia`
+2. `/home/runner/.cargo/bin/mlc README.md --throttle 100` (22-25 seconds - NEVER CANCEL)
+3. Manually verify any new entries follow the format: `- [Name](link) - Description.` (note period)
+4. Check that entries are properly categorized and alphabetically sorted within sections
+5. Verify descriptions are concise (under 100 characters) and end with a period
+
+### Manual Content Validation
+When adding or editing entries:
+- Verify links are accessible and lead to the correct resource
+- Ensure descriptions are concise and accurate (under 100 characters)
+- Check that the resource is actually related to Avalonia UI
+- Confirm entries follow the established format exactly
+- Validate entries are placed in the correct category section
+
+### GitHub Actions Workflow
+- The `.github/workflows/link-check.yml` runs weekly on Mondays at 9 AM UTC
+- Uses `becheran/[email protected]` to check all markdown links
+- Can be triggered manually via GitHub UI using workflow_dispatch
+- Failures are expected due to external site changes - review and update as needed
+
+## Common Tasks
+
+### Adding a New Entry
+1. Identify the correct category section in README.md
+2. Use the exact format: `- [Name](link) - Description.` (note the period at the end)
+3. Insert alphabetically within the category
+4. Validate the link works and description is accurate (under 100 characters)
+5. Run link checker: `/home/runner/.cargo/bin/mlc README.md --throttle 100` (22-25 seconds)
+6. Ensure description follows CONTRIBUTING.md guidelines: short, simple, and descriptive
+
+### Fixing Broken Links
+1. Run full link check: `/home/runner/.cargo/bin/mlc . --throttle 100` (22-25 seconds - NEVER CANCEL)
+2. Review the "broken links" list in the output (expect 40-50 broken links normally)
+3. Research each broken link to find:
+   - Updated URL if the resource moved
+   - Alternative resource if the original is permanently gone
+   - Remove entry if resource is no longer relevant
+4. Update README.md with corrections
+5. Re-run link checker to verify fixes: `/home/runner/.cargo/bin/mlc README.md --throttle 100`
+
+### Updating Categories
+1. Edit README.md table of contents if adding new sections
+2. Ensure internal anchor links match section headers exactly (case-sensitive)
+3. Verify all TOC links work: `/home/runner/.cargo/bin/mlc README.md --throttle 100` (22-25 seconds)
+4. Follow the existing hierarchy: major sections, subsections, and sub-subsections
+
+## Repository Reference
+
+### Exact Entry Format Examples
+**Correct format:**
+```
+- [Avalonia](https://github.com/AvaloniaUI/Avalonia) - Avalonia source code.
+- [AvaloniaVS](https://github.com/AvaloniaUI/AvaloniaVS) - Visual Studio Extension for Avalonia.
+```
+
+**Common mistakes to avoid:**
+- Missing period at end: `- [Name](link) - Description`
+- Wrong bullet format: `* [Name](link) - Description.`
+- Missing space after bullet: `-[Name](link) - Description.`
+- Inconsistent capitalization in descriptions
+
+### Current Structure Output
+```
+ls -la /home/runner/work/awesome-avalonia/awesome-avalonia
+total 68
+drwxr-xr-x 4 runner docker  4096 Sep  9 15:07 .
+drwxr-xr-x 3 runner docker  4096 Sep  9 15:06 ..
+drwxr-xr-x 7 runner docker  4096 Sep  9 15:07 .git
+-rw-r--r-- 1 runner docker   378 Sep  9 15:07 .gitattributes
+drwxr-xr-x 3 runner docker  4096 Sep  9 15:07 .github
+-rw-r--r-- 1 runner docker   649 Sep  9 15:07 .gitignore
+-rw-r--r-- 1 runner docker   397 Sep  9 15:07 CONTRIBUTING.md
+-rw-r--r-- 1 runner docker 36899 Sep  9 15:07 README.md
+```
+
+### Current Link Statistics
+- **Total links**: 299
+- **Working links**: ~246 (82%)
+- **Warnings**: ~9 (redirects)
+- **Broken links**: ~44 (15%)
+- **Check frequency**: Weekly via GitHub Actions
+
+### Key Categories in README.md
+- General
+- Samples and Projects (Audio, Communication, Documents, Gaming, Graphics, Productivity, Software Development)
+- Tutorials
+- Libraries & Extensions (Generic, Localization, Themes, MVVM, Charts, Controls, Games, Web)
+- Videos
+- Articles
+- Community
+- Tooling
+
+## Important Notes
+
+- **NO BUILD PROCESS**: This repository has no compilation, testing, or build steps
+- **NO DEPENDENCIES**: No package.json, requirements.txt, or similar dependency files
+- **CONTENT FOCUS**: Primary work involves curating and organizing Avalonia-related resources
+- **LINK MAINTENANCE**: Regular validation and updating of external links is the main maintenance task
+- **COLLABORATIVE**: Follow CONTRIBUTING.md guidelines when adding community suggestions
+
+## Troubleshooting
+
+### Link Checker Issues
+- If mlc is not installed: `cargo install mlc`
+- If Rust/Cargo is not available: Install Rust toolchain first
+- If links fail due to rate limiting: Increase `--throttle` value (e.g., `--throttle 200`)
+- If checker hangs: Wait at least 60 seconds before considering alternatives
+
+### Content Issues
+- Verify entry format matches existing entries exactly
+- Check that links use HTTPS when available
+- Ensure descriptions end with a period
+- Confirm alphabetical ordering within categories
+- Validate that new categories have corresponding TOC entries