Remove gh.md import and enable GitHub MCP for issues in dev.md

- Removed shared/gh.md import from dev.md
- Enabled GitHub MCP with toolsets: [issues] to allow reading issues
- Changed github tool from false to configured with issues toolset
- All workflows compile successfully (107/107)
- Reduced warnings from 71 to 70

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

Author: Copilot