feature: Add GitHub Copilot support (CLI and CHAT) ‼️‼️‼️

[npkriami18]

Adds MCP server integration for:

• GitHub Copilot (VS Code Extension)
• GitHub Copilot Chat (VS Code)
• GitHub Copilot CLI

Uses --platform copilot for VS Code variant
Uses --platform copilot-cli for CLI variant

Platforms now: 10 (was 8)

[tirth8205]

Thanks for adding Copilot support! The structure is solid. A few issues to fix:

1. CHANGELOG version regression. The PR adds a [2.1.1] entry, but we're already at [2.2.1]. Please remove the CHANGELOG entry — we'll add it when we cut the next release.

2. Detection is too broad. _copilot_vscode_detected returns True if any VS Code directory exists — but that proves VS Code is installed, not Copilot. Every VS Code user would get Copilot MCP config injected. Other platforms check for platform-specific directories. Consider checking for the Copilot extension directory instead (e.g., ~/.vscode/extensions/github.copilot-*).

3. Writes to VS Code's global settings.json. This is more invasive than other platforms which use dedicated config files. A misconfigured write could corrupt VS Code settings. Please add extra caution here (e.g., validate the JSON structure before writing).

4. Tests are shallow. The existing TestPlatformInstall tests verify actual file writes and JSON structure. Please add similar tests for Copilot (not just that detect() returns a bool).

[npkriami18]

Thanks for adding Copilot support! The structure is solid. A few issues to fix:

1. CHANGELOG version regression. The PR adds a [2.1.1] entry, but we're already at [2.2.1]. Please remove the CHANGELOG entry — we'll add it when we cut the next release.
2. Detection is too broad. _copilot_vscode_detected returns True if any VS Code directory exists — but that proves VS Code is installed, not Copilot. Every VS Code user would get Copilot MCP config injected. Other platforms check for platform-specific directories. Consider checking for the Copilot extension directory instead (e.g., ~/.vscode/extensions/github.copilot-*).
3. Writes to VS Code's global settings.json. This is more invasive than other platforms which use dedicated config files. A misconfigured write could corrupt VS Code settings. Please add extra caution here (e.g., validate the JSON structure before writing).
4. Tests are shallow. The existing TestPlatformInstall tests verify actual file writes and JSON structure. Please add similar tests for Copilot (not just that detect() returns a bool).

Thank you for the feedback! I've addressed all the points:

• Removed the [2.1.1] entry from the CHANGELOG to avoid the version regression.
• Updated _copilot_vscode_detected to specifically check for the Copilot extension directory (e.g., ~/.vscode/extensions/github.copilot-*), making detection more accurate.
• Added extra validation before writing to VS Code's global settings.json to ensure the JSON structure is correct and prevent potential corruption.
• Expanded the Copilot-related tests to verify file writes and JSON structure, similar to the TestPlatformInstall tests.
• Please let me know if any further changes are needed!